I need to convert .odt file to .doc file to email using Thunderbird because gmail isn’t supported. How do I do it?
Why .doc? Why not .docx? Passwords in .doc files are not safe. You could protect the file with a password, but this is not encryption - it’s only password protection of the file. Encryption is possibly not an LO topic to discuss here.
As @Hrbrgr wrote: Save as, select your prefered file type, and in addition tick with password, save. Option encrypt with GPG will only work if you have respective keys and certs as your recipient would need too (at least your public key) and I’d suspect that this LO GPG feature is not compatible with file format doc/docx nor with target software assuming MS Word.
Open LibreOffice. Open your file. Save with Save as. Select the file type “doc”. Click Save.
But this does not answer how to encrypt that file, right?
OK, yes you’re right.