remarks column; notes field
A designated space on a form, document, or database for additional notes or comments.
申込書の備考欄に特記事項を記入してください。
Please write any special notes in the remarks column of the application form.
備考欄には何も書かなくても大丈夫です。
It's okay to leave the notes field blank.
Compound of 備考 (bikō, 'reference note') + 欄 (ran, 'column').