HTML is the right choice when layout, headings, images and links need to be presented together. Plain text is better when portability, searchability and a predictable reading order matter more.
Choose plain text for a clean handoff
Use it for notes, archives, quotes, terminal workflows and any place where invisible formatting creates more work than value. Link URLs and list bullets can still be kept when they are useful.
Keep both when in doubt
Save the original HTML when you may need the design later. Use the clean text as the copy you send or reuse today.
Convert HTML to plain text without sending it to a server.