Correct spelling, explanation: this form, submission, comes from Latin submissionem, so it should be written with double s. The core word is the verb submit, which also looks similar in Latin (submittere), so there is continuity in taking this word from Latin. Therefore submition is an incorrect form, and submission is the correct one.

Definition of submission:
noun, something submitted or an act of submitting something for approval or submitting under control
This college submission deadline is next week.
I gave in submission for tax return and now I just have to wait.

Incorrect spelling, explanation: although ending -sion and -tion are pronounced a similar way, in the case of submission the correct form is double s option, because it comes directly from Latin (submissionem). Submition is therefore a mistake and the correct form is submission.

Incorrect spelling

Incorrect spelling

Incorrect spelling

Incorrect spelling