A date used to indicate the day an event happened or the date written on a document.
契約書には必ず署名と日付を入れてください。
Please be sure to include your signature and the date on the contract.
レポートの日付は提出日を記入すること。
For the report date, write the submission date.
古い手紙を見つけて、日付を調べた。
I found an old letter and checked the date on it.