Fetching details from the dictionary...
to affix; to append; to attach
to entrust; to refer; to handle (as such)
to follow (the leader)
to submit (a document, etc.)
書類に注釈を付した。
I appended a note to the document.
手紙にメモを付している。
I am attaching a memo to the letter.
報告書に別添資料を付する予定だ。
I plan to attach supplementary materials to the report.