punctuation mistakes

It is difficult to give punctuation advice without a complete sentence.  Looking at this mostly (or most) commonly used is a fragment.

If you have a question about the software itself, you should email support.

I would say, "Looking at this most commonly used..." instead. "Commonly" is one of those adverbs that is usually modified by intensifiers like "very" or "so", rather than general adverbs. You can say "mostly used" or "commonly used", but not both, because the adverbs are fighting of the same slot in the syntax. I hope that helps.