Is it okay to make a commercial video with the default fonts on FCPX iPad?

Hi 

I recently downloaded a Final Cut pro on my iPad and used the fonts available in FCPX for

editing a YouTube video. I’m wondering if it’s possible to use the default fonts for commercial videos.

Previously, when using Premiere on my Mac, I would download free fonts, 

but I’m not sure how to do the same on my iPad. 

If anyone has experience with this issue, I would greatly appreciate your advice. 

Thank you in advance!