Guides.
Step-by-step guides to creating, converting and automating documents: invoices, PDFs, barcodes and the file formats around them.
What Is an Invoice?
What is an invoice? A seller's request for payment. See a labeled example, required fields, invoice vs receipt vs bill, invoice types and payment terms.
What Is an Invoice Number?
What is an invoice number? The unique ID on every invoice. See 5 formats with examples, where to find it, US rules, and how to fix skips and duplicates.
How to Send an Invoice
How to send an invoice by email or payment link, with a copy-paste invoice email template and a follow-up schedule to help you get paid on time.
Contractor Invoice Template (Free Word, Excel, PDF)
Download a free contractor invoice template in Word, Excel or PDF, with a filled-in example: labor, materials, change orders, retainage and sales tax.
How to Automate PDFs Without Code (2026 Guide)
Three practical ways to automate PDF work without writing code: AI-drafted flows, no-code platform modules in Make/Zapier/n8n, and free web tools.
What Is Document Workflow Automation? A Plain-Language Guide
Document workflow automation explained without jargon: what it is, what it replaces, when you need it, and how non-technical teams automate PDFs.
PDF to HTML — What Survives the Conversion (and What Breaks)
Converting PDF to HTML: why PDFs have no real structure, responsive vs fixed-layout output, and how to keep tables and reading order intact.
Static vs Dynamic QR Codes — Which One Do You Need?
Static QR codes never expire and cost nothing to keep alive. Dynamic ones are editable and trackable but depend on a vendor. Here is how to choose.
GTIN, UPC, EAN and GS1 Explained (With Check Digits)
What a GTIN is, how it differs from UPC and EAN, where to get one, how the check digit is calculated, and what GS1 Sunrise 2027 changes for 2D barcodes.
How to Create an Invoice — Fields, Numbering & Automation
What every invoice must contain, how to number them, and three ways to create one: a free generator, a spreadsheet template, or an invoicing API.
llms.txt Explained — Format, Example File, and Setup
What llms.txt is, the exact file format, a copy-paste example, and whether it helps AI engines cite your site. A practical 10-minute setup guide.
Convert Bank Statements to CSV or Excel — 4 Ways
Four ways to convert PDF bank statements to CSV, Excel, QBO or OFX — manual, spreadsheet tricks, OCR, and purpose-built extraction with reconciliation.
Markdown to PDF — Convert MD Files via API
Convert Markdown to PDF with one REST call: styling, page breaks, code blocks and tables handled. Why devs are ditching pandoc setups. Free tier.
Generate Barcodes Programmatically: Formats, Sizing and Print Accuracy
How to generate barcodes in code: choosing Code 128, EAN-13, QR or GS1, getting quiet zone and module width right, and embedding them in PDFs.