User Guide for Mac > Save a note as plain text
Save a note as plain text - JustNoteIt for Mac help
How to save notes in txt format
To save a single note in one of these formats, choose "Save as" from the Note's menu or press Alt + Command + S, from the file format choose choose where to save the file.
To save a group of notes as text files, highlight them in the Notes Manager and do any of the following Control + click and choose Save as or choose Notes > Save as or use the Option + Command + S shortcuts combination.
See also:
Save notes as pdf
Export notes to rtf and rtfd format
Export notes to Word