Free Tool Guides

No-Fluff Guides

Practical guides, tutorials, and explanations for the tools and workflows available on 101 Tech Labs.

All Guides (44)

How to Make an Invoice: A Step-by-Step Guide

What every invoice needs, how to format one, and how to send it so you get paid on time — with a plain checklist you can reuse for every client.

8 min read

Invoicing

Invoice Payment Terms Explained: Net 30, Net 15, and Due on Receipt

What Net 30, Net 15, and Due on Receipt actually mean, how to pick the right terms for a client, and how to write them so there’s no ambiguity about when you get paid.

7 min read

Invoicing

How to Number Your Invoices (Without Losing Track)

A simple, sustainable invoice numbering system — sequential, date-based, or client-based — plus how to fix a numbering system that’s already inconsistent.

6 min read

Invoicing

How to Get Paid Faster: Practical Ways to Speed Up Invoice Payments

Concrete, low-effort changes to your invoicing process — clearer invoices, upfront deposits, and better timing — that shorten how long clients take to pay.

9 min read

Invoicing

Invoice Late Fees: How to Charge Them the Right Way

How to structure a late fee, add it to your invoices and contracts, and enforce it without damaging a client relationship you want to keep.

7 min read

Invoicing

How to Accept Online Payments on Your Invoices

Compare ways to accept credit card, ACH, and other online payments on invoices — fees, setup effort, and how offering one cuts payment friction and gets you paid faster.

7 min read

Invoicing

Invoice Follow-Up: How to Ask for Payment Without It Being Awkward

A professional invoice follow-up process — timelines, sample wording, and escalation steps — that gets you paid faster without straining the client relationship.

7 min read

Invoicing

Invoice Reminder Templates: What to Send and When

Ready-to-use invoice reminder templates for every stage — before due, due today, and overdue — plus guidance on timing and tone to get invoices paid faster.

7 min read

Invoicing

Overdue Invoices: A Step-by-Step Guide to Getting Paid

A step-by-step guide to handling overdue invoices professionally — when to follow up, how to escalate, and how to protect the client relationship while you do it.

9 min read

Invoicing

Collection Letter Templates for Unpaid Invoices

Free collection letter templates for every stage of an unpaid invoice — from a first formal notice to a final demand — with professional wording that avoids damaging the relationship.

7 min read

Invoicing

Bad Debt: What It Is and How to Reduce It

What bad debt is, why invoices become uncollectible, how to spot the warning signs early, and practical ways to reduce bad debt and protect your cash flow.

7 min read

Invoicing

Quote vs Invoice: What’s the Difference?

The difference between a quote and an invoice, when each becomes legally binding, and how both fit into your sales workflow — with plain examples.

6 min read

Invoicing

Estimate vs Quote: What’s the Difference?

What an estimate and a quote each mean, when to use one over the other, how they lead to an invoice, and which one to send your customer first.

6 min read

Invoicing

Invoice vs Receipt: What’s the Difference?

Invoice vs receipt, explained simply: an invoice asks for payment, a receipt proves it. Learn when to use each, what to include, and how they fit together.

6 min read

Invoicing

Invoice Statuses Explained: Draft, Sent, Overdue, Paid, Void

Draft, sent, overdue, paid, void — learn what every invoice status means and exactly what to do next at each stage of the invoice lifecycle.

6 min read

Invoicing

Credit Notes: What They Are and When to Issue One

What a credit note is, when to issue one, and how it differs from an invoice, refund, and receipt — with examples and a step-by-step template.

6 min read

Invoicing

What Is a Purchase Order? A Plain-English Guide

What a purchase order is, how POs work, what they include, and how they differ from quotes and invoices — with a real example.

6 min read

Invoicing

Purchase Order vs Invoice: What’s the Difference?

Purchase order vs invoice explained simply: the buyer sends the PO to authorize a purchase, the seller sends the invoice to request payment.

5 min read

Invoicing

What Is a Receipt? When to Issue One and What to Include

What a receipt is, when to issue one, what to include, and how it differs from an invoice and a payment confirmation — with a sample receipt and template.

6 min read

Invoicing

Commercial Invoice: What It Is and When You Need One

What a commercial invoice is, when it’s required, and every field it must include — so your international shipments clear customs without delays.

7 min read

Invoicing

Pro Forma Invoice: What It Is and When to Use One

A pro forma invoice communicates expected costs before payment is due. Learn what it is, when to use one, what to include, and how it differs from an invoice.

6 min read

Invoicing

Recurring Invoices: How to Automate Billing for Repeat Clients

What recurring invoices are, when to use them, and how to automate billing to get paid on time. A practical guide for freelancers and small businesses.

7 min read

Invoicing

Customer Statements: What They Are and When to Send Them

What a customer statement is, how it differs from an invoice, what to include, and when to send one so you get paid faster on outstanding balances.

6 min read

Invoicing

Invoice Deposits: How to Request Upfront Payment the Right Way

When and how to request invoice deposits and partial payments, how much to ask for, and sample wording to get paid upfront without losing clients.

7 min read

Invoicing

Progress Invoicing: How to Bill Large Projects in Stages

Progress invoicing lets you bill large projects in stages as work is completed — how it works, methods, a worked example, and how it differs from deposits.

7 min read

Invoicing

Payment Plans: How to Offer Installments Without Hurting Cash Flow

How to offer customer payment plans that improve collections and protect relationships — when to use them, how to structure installments, and sample wording.

7 min read

Invoicing

Retainer Agreements: How They Work and How to Invoice Them

How retainer agreements work, the main types, how to invoice a retainer, and how they differ from recurring invoices, deposits, and progress invoicing.

7 min read

Invoicing

Cash Flow: A Plain-English Guide for Small Businesses

A plain-English guide to small business cash flow — what it is, why it beats profit as a health signal, 10 ways to improve it, and how to forecast it.

8 min read

Invoicing

Gross Profit vs Net Profit: What’s the Difference?

Gross profit shows if your work is profitable; net profit shows if your business is. Learn the difference, how to calculate each, and what the margins mean.

6 min read

Invoicing

How to Read Financial Statements: A Beginner’s Guide

Learn how to read the income statement, balance sheet, and cash flow statement in plain English — and use them to make smarter business decisions.

9 min read

Invoicing

How to Price Your Services: A Practical Guide

How to price your services with confidence — pricing models compared, a step-by-step rate formula, worked examples, and how to raise prices.

9 min read

Invoicing

Accounts Receivable: A Plain-English Guide for Small Businesses

A plain-English guide to accounts receivable for small businesses. Learn the AR process, key metrics, common mistakes, and how to get paid faster.

8 min read

Invoicing

Invoice Aging Report: What It Is and How to Use One

Learn what an invoice aging report is, how to read the aging buckets, and how to use it to prioritize collections and get paid faster — with a sample report.

7 min read

Invoicing

Days Sales Outstanding (DSO): What It Is and How to Reduce It

What Days Sales Outstanding is, the DSO formula, a worked example, what counts as a good DSO, and practical ways to reduce it and get paid faster.

7 min read

Invoicing

Accounts Receivable Turnover Ratio: What It Is and How to Calculate It

What the accounts receivable turnover ratio is, how to calculate it with a worked example, what counts as a good ratio, and how to improve collections.

6 min read

Invoicing

Cash Application: How to Match Payments to Invoices

Cash application is how you match customer payments to the right invoices. Learn how it works, why it matters, and best practices to keep balances accurate.

7 min read

Invoicing

Payment Reconciliation: A Step-by-Step Guide

Payment reconciliation in plain English: what it is, why it matters, and a step-by-step process to match every payment to its invoice and bank deposit.

7 min read

Invoicing

Invoice Disputes: How to Resolve Them Without Damaging the Relationship

A practical guide to resolving invoice disputes without damaging client relationships. Step-by-step responses, sample wording, and prevention tips.

8 min read

Invoicing

Working Capital: What It Is and How to Calculate It

Working capital is the cash your business can use right now. Learn what it is, how to calculate it with the formula, and how to improve it — with examples.

7 min read

Invoicing

Revenue Forecasting: Simple Methods for Small Businesses

Learn simple revenue forecasting methods for small businesses and freelancers — historical trend, pipeline-based, and run-rate approaches, with a worked example.

8 min read

QR Codes

How to Make a QR Code: A Step-by-Step Guide

How to pick the right QR code type, keep it scannable after printing, and understand the difference between static and smart-redirect codes — with a practical checklist.

7 min read

Developer Tools

How to Test an API: A Beginner’s Guide to HTTP Requests

What "testing an API" actually means — HTTP methods, headers, query params, request bodies, and auth — with a practical walkthrough of building and reading a request.

10 min read

Developer Tools

What Is a CORS Error, and How Do You Fix It?

Why "blocked by CORS policy" shows up in your console, what’s actually enforcing it, and the real ways to fix it depending on whether you control the API.

7 min read

Developer Tools

How to Write DBML: A Guide to Diagramming Your Database Schema

DBML syntax explained — tables, columns, column settings, and Ref relationships — with a practical walkthrough of writing a schema that renders as a diagram.

9 min read

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