Guides
Practical guides for creating QR codes, taking passport photos, combining photos into a PDF, working with images and pricing card payments.
How to create a QR code
Pick the right QR code type, size it for the scanning distance, keep the contrast and margin right, and why a static code never expires.
How to create a WhatsApp QR code
Make a QR code that opens a WhatsApp chat with your number and a ready message. The number format that works, where to use it and what to check.
How to create a Wi-Fi QR code
Let guests join your Wi-Fi by scanning a code. Which security type to choose, why a guest network is safer, and what happens when the password changes.
How to compress an image without uploading it
Make a photo small enough for a form, an email or a website without visible loss: resize first, the quality setting that works, and which format to use.
JPG vs PNG: which format to use
JPG for photos, PNG for text, logos and transparency, WebP for the web. What each one does, and what goes wrong when you convert between them.
How to take a passport photo at home
Take a 2x2 passport photo with your phone, check it against the official rules and print six of them on one 4x6 print for well under a dollar.
Card machine fees in Brazil: how much to charge
Why adding the fee percentage to your price leaves you short, the formula that works, and how debit, credit, instalments and payout time change the fee.
How to combine photos into one PDF
Turn several photos of documents or receipts into a single PDF on your phone or computer, without uploading them, plus built-in ways on iPhone and Windows.
How to spot a fake boleto
Where fake boletos come from, the checks that catch them before you pay, and what to do if you already paid one. A plain-language guide for Brazil.
How to request a Pix payment on WhatsApp
Send a Pix charge on WhatsApp that customers can pay in two taps: the copy-and-paste code, the amount and what it is for, plus how to avoid fake receipts.
How to remove location from a photo
Phones save your GPS position in every photo. See how to check it, strip it before sharing and stop your camera from recording it, on iPhone and Android.