I am unable to download any apps from the App store. It keeps asking for Apple id password and once I enter is comes to the payment

To be able to download apps from the AppStore, you payment information has to be complete and supported.

Have a look at the steps mentioned in the related article to check:

If you need to change or update your Apple ID payment method - Apple Support

Also, there has to be some Apple ID balance left, to be able to download or update apps.

You can top up your Apple ID balance by using Apple Gift Cards, if your payment method is working.

What you can buy with your Apple Gift Card or Apple Account balance - Apple Support