noun
date of issue; date of publication
Used for the date a document, certificate, ticket, or publication was officially issued or published.
パスポートの発行日を確認してください。
Please check the date of issue on your passport.
この本の発行日は2020年4月1日です。
The publication date of this book is April 1, 2020.
発売日 is the date something goes on sale, while 発行日 is the date it is officially issued or published.
Compound of 発行 (issue, publication) and 日 (day).