How to Save an Email as a PDF?

Outlook (desktop / Microsoft 365)

1. Open the message.
2. File → Print, or Ctrl+P (Cmd+P on Mac Outlook).
3. Printer: Microsoft Print to PDF (Windows) or Save as PDF (Mac).
4. Print/Save and pick a folder.

Outlook on the web: Open the message → ⋯ → Print → in the browser print dialog, destination Save as PDF.

Gmail (browser)

1. Open the thread.
2. ⋮ → Print, or Ctrl+P / Cmd+P.
3. Destination Save as PDF (Chrome/Edge).

Apple Mail: Open the message → File → Export as PDF, or Print → PDF → Save as PDF.

Attachments: print-to-PDF usually captures the message body, not every attached file as pages inside that PDF. Save attachments separately if you need those files too.

Long threads: Print often includes the open conversation. Expand or choose "this message only" if your client offers it, so you don't get a 40-page PDF of quotes.

Parent-topic searches often say Outlook; the same print-to-PDF trick is what Gmail and Mail are doing under a different menu name.

The closest sibling pages are How to Screenshot on an HP Laptop? and How to Search Words on a Page?.

See other Phones, Computers & Devices questions for other answers in this topic, or start from more researched answers.