Accessing code to make accessibility changes

I am developing an app, and after having a 3rd party vendor do a digital accessibility audit on it, I received a lengthy list of remediations that must be made. Much of the instructions on how to fix are similar to the screenshot shown below. My problem is that I’m not sure how to access this code. Is this possible, and if so, how do I do it?
Thank you!

This isn’t possible to do in Glide, AFAIK

I have a sense some of this can be done using CSS, but if you’re going to have a lot of this, it would take a lot of time. I haven’t seen any people complaining about something like the one in your screenshot, to be honest.