It is the only way notes leave Evernote, and almost nothing opens it directly.
Convert an .enex file to Markdown
An `.enex` is one XML file holding every note you exported: the title, the tags, the dates, and the note itself as ENML — Evernote’s own restricted flavour of XHTML — wrapped inside the XML. Attachments travel in the same file, base64-encoded, linked to the note by the MD5 of their contents rather than by name.
Select the notes, or a whole notebook, then File, Export notes. The desktop app writes `.enex`; the web app does not offer an export at all, so this is a desktop-only operation.
Export a notebook at a time rather than everything at once. A single file of ten thousand notes is one thing that can go wrong instead of twenty.
Obsidian’s Importer plugin, Notion’s import, Apple Notes, Joplin and Bear all accept `.enex` — because it is the format everybody wrote an importer for when Evernote’s pricing changed. What does not read one is a text editor: open it and you get XML with your notes inside base64 and CDATA.
Tags, first. They are how an Evernote library is organised and several importers drop them, at which point ten thousand notes are a pile rather than a library.
Then attachments. A note that had a PDF or a photograph in it should still say so, and the format links the two by a hash rather than a filename — which is where an importer that took a shortcut shows it.