All android phones come with a file manager, no? Even if it somehow didn't, you can certainly install one, and I would be surprised if it didn't have the option to share the file regardless of file type.
Anything from F-Droid will certainly have this or you can try Fossify File Manager on the Play store.
edit: Ah I see you can't find the text file. The editor probably has a "Save as" button to save it to accessible storage,or get a better text editor (Material Files on F-Droid has one built in).