iphone 5s not support download youtube

If you can't download, make purchases or update apps, including free apps, you need to update your payment method or add a new one. If you already verified that a payment method is available in your country or region and you're still having trouble, learn more.

iPhone 5s, iOS 12

iOS 12.5.7 is the latest iOS security update for iPhone 5s.

👉 iPhone 5s can’t be update to a higher iOS (13 and later). 

If you have an outdated iPhone that cannot be updated any more, many apps will not be able to download.

Outdated iPone no longer meets the requirements for many apps.

Most apps required iOS 13.4 or later.  

Google Docs requires iOS 15.0 or later.

Spotify requires iOS 14.0 or later.

YouTube requires iOS 14 or later. 

You can still use:

WhatsApp requires iOS 12.0 or later. 

Snapchat requires iOS 12.0 or later.

If one or more of the following 6 options are true then you can't choose None as a payment method then the Billing information is needed . The "None" option will not appear...

1. If you have an unpaid balance or payment due
2. If you have a subscription that automatically renews
3. If you're using the iTunes Store or App Store for the first time
4. If you are not in the country or region you’re creating an Apple ID for
5. If you changed your country or region
6. If you're a part of Family Sharing

I think the OP's problem is that some apps that he wants to download require a later version of iOS than his phone can run.

Google Docs, for instance, "Requires iOS 15.0 or later" according to its App Store Preview page. An iPhone 5s like the one that the OP has cannot run iOS 13 or above. If the App Store is not offering old versions of that app, then the OP's choices are to (1) go without the app, or (2) get a newer phone.

Is not there any way to run YT on 5s?

No, you cannot install YouTube on an iPhone 5S.

Youtube requires iOS 14 or higher, the iPhone 5S can't be updated beyond 12.5.7.

Try using the web version.