How can i make the archive file format be like "$file.archive.org"

[alanfzf]

I want the archive file to have the format of .archive.org is this possible?

[cookesan]

Yes, if file.org.archive.org is the format you want, set org_archive_location like this:

require('orgmode').setup({
  org_archive_location = '%s.archive.org::',
})

%s is replaced with the current file name, and :: is the archive-location separator. So for todo.org, this produces todo.org.archive.org in the same directory.

If you meant todo.archive.org instead, with the original .org extension removed, I do not think there is a global format string for that. The implementation formats with the current file name directly. For a specific file you can set the exact archive path with an org keyword instead:

#+ARCHIVE: todo.archive.org::

That per-file #+ARCHIVE value overrides the global org_archive_location.