submission deadline; due date for submission
Refers to the deadline by which something must be submitted, such as a report, application, or assignment.
The submission deadline for the report is next Friday.
If you miss the submission deadline, it won't be accepted.
締め切り is a general term for any deadline or closing date, while 提出期限 specifically refers to a deadline for submitting something.
Compound of 提出 (ていしゅつ, 'submission') and 期限 (きげん, 'deadline' or 'time limit').