添付 and 同封: attaching a file and enclosing an item
Learn email-attachment and postal-enclosure contexts, separating a statement about an attachment from checking that it is actually present.
Attaching supporting material
添付, read てんぷ, means attaching supporting material to a document or file. メールに資料を添付しました。 says that materials were attached to the email.
添付ファイルを開いてください。 asks someone to open the attached file. 添付 often appears with digital files, but it can also describe supporting material attached to documents.
Putting items in the same envelope or package
同封, read どうふう, means enclosing something in the same envelope or package. 返信用の封筒を同封しました。 says that a reply envelope was enclosed.
同封の用紙に住所を書いてください。 asks someone to write an address on the enclosed form. The form is included in the same mailing rather than arriving separately.
Checking the medium and its contents
資料はメールに添付しました。郵便で送る手紙には、返信用の封筒を同封しました。 says that materials were attached to the email and a reply envelope enclosed in a letter sent by post. Track which medium carries each item.
資料を添付するのを忘れました。 says that attaching the materials was forgotten. Wording such as 添付しました in the message and the actual presence of an attachment need separate checking.
Does 同封の用紙 mean that the form will arrive in a different mailing?
Show the answer and why
No. It refers to a form included in the same envelope or package.