A file format is the blueprint for how data is stored inside a file - its structure, encoding, and rules. The format tells apps how to read, write, and display what’s inside (text, images, audio, spreadsheets, etc.).
Pick the right format and your file opens everywhere, looks correct, and stays useful years later. Pick the wrong one and you get garbled text, missing fonts, or “can’t open this file” errors.
Documents: .txt, .docx, .pdf
Images: .png, .jpg, .svg, .webp
Audio/Video: .mp3, .wav, .mp4, .mkv
Data: .csv, .json, .xml
Archives: .zip, .7z, .rar
Open/standard (e.g., PDF, CSV): broad compatibility, good for sharing/archiving.
Proprietary (e.g., some project files): powerful features, but may lock you to one app.
Share/Publish: use PDF for layout-perfect docs, PNG/JPG for images, MP4 for video.
Edit later: keep a source file (e.g., .docx, layered .psd/.afphoto) and export a shareable copy.
Data work: prefer CSV/JSON for portability.
Long-term: choose open, well-documented formats to avoid future lock-in.