Why can’t I download apps?

i just upgraded my iPhone from a 5s to a 5se. I’m trying to download my apps onto my new phone & it is not allowing me to do so. It continuously asks for my apple ID password, goes to my billing, I accept and it repeats this cycle. It’s very frustrating, I’ve signed in & out of my ID, I’ve restarted the phone, adjusted my internet, and applied the ios update and still cannot download my apps