In mukātabah, the teacher sends a written hadith or transmission record to a pupil. This may be accompanied by explicit authorization or may occur without such permission. Earlier scholars included those who accepted carefully authenticated written transmission; permission clarifies the authorization.
Example: A teacher sends a student in another city a letter containing an isnād and matn. If its authorship is reliably established, this supports written reception of the text. Receipt of a letter, however, is not a direct listening session.
Verification matters: preserve the written wording, authenticate its origin, and identify any permission granted. Mukātabah is different from wijādah: in the former, the teacher addresses the writing to the student; in the latter, the student finds an existing text.