Title is default as H2, not H1

As you can see in this photo, the ThemeForest I purchased sets the title as H2, which is supposed to be H1. Just figured it out recently when my blog could not move up the Google ranking. Please help me fix it. Thank you so much!

Do you want it to be H1 or H2, if it’s currently H1 then it’s correct.

I want it to be H1. It’s currently H2

Just add some CSS codes to make it look like H1 instead of editing the whole theme. It would be easier.