書(か)き込(こ)むto fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store

動画(どうが)の概要(がいよう)欄(らん)に動画(どうが)への思(おも)いを書(か)き込(こ)む。

Write your thoughts about the video in the video's description section. {to fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store}

申込(もうしこみ)書(しょ)に氏名(しめい)と生年月日(せいねんがっぴ)と連絡(れんらく)先(さき)を書(か)き込(こ)みました。

I filled out the application form with my name, date of birth, and contact information. {to fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store}

欄外(らんがい)に書(か)き込(こ)まれている注(ちゅう)は文字(もじ)が小(ちい)さくて読(よ)みにくいです。

The notes written in the margin are small and hard to read. {to fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store}

教科書(きょうかしょ)の余白(よはく)に先生(せんせい)が言(い)った大事(だいじ)なことを書(か)き込(こ)むようにしている。

I make it a point to write down important things the teacher said in the margins of the textbook. {to fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store}

答(こた)えを直接(ちょくせつ)ワークブックに書(か)き込(こ)んでしまったら、一(いち)度(ど)しか問題(もんだい)を解(と)けなくなります。

If you write the answer directly in the workbook, you will only be able to solve the problem once. {to fill in (field, entry, etc.), to fill out (form), to post a message (e.g. on a bulletin-board), to store}