noun, noun or participle which takes 'suru'
attachment; appendix; addendum
Refers to a supplementary document or file attached to a main document, often in formal or business contexts. Can be used as a noun or with する to mean 'to attach'.
契約書に別添の資料をご確認ください。
Please check the attached materials to the contract.
メールにファイルを別添します。
I will attach the file to the email.