Change font size promo box and promo on fonts size H2

Hey people so I am busy with my website and I want to change font size from de promobox and I have a problem with de font size H2, when I select to be bigger ik looks like is changed, but after I save, it goes back to the size of 16. Someone that can help me fiz this 2 things ?

Thank you

Hi there,

Can you share your site URL here?

hi awan hier is my website

Thank you, but can you point it to me which area that you want to change?
I can’t find the promobox section that you mentioned above.