Web view, external html o css

I salute the Kodular community.

My question is very simple, but I don’t know how to execute it. I have a PWA, but I want to execute an external code to delete the Header and Footer of a <Display: none;> What should I do, is it feasible? Only that, I don’t ask for more but I can’t find a solution in the forums. I appreciate your responses. I love this community!