I'll append no less than TEN "P.S."s to the end of my letter. Awkward!
For every fire, Heaven appends some rain. For every rain, Heaven appends some fire. Thus is the balance of life restored.
A formal word for "to append" or - better yet - "to be included"
. To go along with, to accompany (not used with people - in that case you'd say 伴う（ともなう）） 添える is more like, the CDR comes with the textbook. Or the applesauce comes with the pork chops.
attatch (a file to your email) (read the attached instructions)
伴う 同伴する 添える 添付