Correct spelling, explanation: this word is a present participle/gerund of the verb submit. The correct version consists of the double -t letter. It comes from Latin submittere and the etymology signalizes this kind of spelling. It’s worth mentioning that when we create a present participle of a verb and there is a single vowel before the last, stressed consonant in it, we need to double that consonant. Submitting is the only correct spelling and submiting is incorrect.

Definition of submitting:
verb (present participle), to yield or give way to another
The rioters are submitting to the authorities right now.
She said that she was submitting to threats.

Collocations with submitting:
Some most commonly used collocations include: submit for publication, submit for analysis.
This article was submitted for publication earlier this year.
Samples collected from corporate products were submitted for analysis.

Incorrect spelling, explanation: when spelling the word submitting, you have to remember to double the -t letter. Why? Because of its popular role in the English language, according to which the last (and stressed as well) consonant in a word must be doubled if there is a single vowel before it. That is the reason why the right form is submitting, not submiting.