Why can’t I download free Apps?

See >>> https://support.apple.com/en-ca/HT203905 on why you can't use NONE as your payment method.

[Edited by Moderator]

All Apps which offer "In-App" purchases, which covers MOSTS free apps require a form a payment tied to your account. That's just how it is. Either put a credit card on your account or buy Apple Gift Cards and add them to your Apple Wallet or don't download any app which offers in-app purchases.

i use my mobile phone as a payment method, after purchasing apps i wanted to download apps but i cant because it requires verification but after filling up everything and after puting balance to my prepaid it still says that i have insufficient balance when i am not purchasing anything that needs payment. please help meee:((