Hi I can download any apps on my phone

Read this document from Apple.

https://support.apple.com/en-gb/ht207165

Hi

Before you can download anything from apps store you need a payment method.

Go to iTunes main page bottom of page apple I'd click that view I'd Go to manage payments check add your debt / credit card.

If you don't have a credit card buy a iTunes gift card redeem at the bottom of iTunes page.

Cheers

Brian 🇬-1F1E7;