pay for items from apple store with paypal credit

By Apple Store you mean the hardware Apple Store? where you can buy iPhones and Macs?

Or do you mean the iTunes Store, where you buy songs, movies and apps?

They are 2 different stores, and have different requirements for payment methods.

If you need to use Paypal for the iTunes store, you need to setup the Payment method for your Apple ID as Paypal using iTunes on a computer. It cannot be done on an iOS device.

Change or remove your Apple ID payment information - Apple Support

The Paypal account requires a linked credit card to be able to be used as payment for the iTunes store.

Payment methods that you can use in the iTunes Store, App Store, and iBooks Store - Apple Support

If you are referring to the Hardware Apple Store, then Paypal can be chosen when checking out as a method of payment but not on the iOS Apple Store app, only through the website.

https://www.cnet.com/news/apple-store-now-lets-you-buy-items-via-paypal/

Methods of payment for online Apple Store, and iTunes Stores, are outlined as follows:

Payment, Financing, Refunds and VAT - Shopping Help - Apple

Payment methods that you can use in the iTunes Store, App ...

Before you can buy anything from the iTunes Store, App Store, and iBooks Store,

or join Apple Music, ... the accepted payment methods are Visa, ...

//support.apple.com/en-us/HT202631

The first linked-section above includes details about using PayPal to buy purchases.

Hopefully you can make use of that to further see how the system is set up. There

may be different methods or rules of payment, depending on your region or country.

Note: different rules apply to iTunes, App Store, and topics in section directly above.

On a separate topic, this applies where Apple ID & payment info is in your records:

Change or remove your Apple ID payment information

... iCloud, iMessage, the Apple Online Store, ... that you use your Apple ID. If you change

your payment method, ... payment wasn't accepted, ...

//support.apple.com/en-us/HT201266

Good luck & happy trails! 🙂

There may be a difference between the rules in region and other country sites.

You may try contacting Apple's iTunes store directly for billing/payment issues.

Or Apple Store, if that is where the issue appears to conflict with printed word.

Perhaps some other person with ideas will/have added some here.

I've added 'official linked info' on site pages. (Edited)

Good luck & happy trails! 🙂