I want to download Facebook on this iPhone

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.

If 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

An iPhone 6plus can run iOS 12.5.7, nothing higher.

Facebook requires iOS 13.4 or higher. You cannot install Facebook on your old iPhone.

Either buy a newer phone capable of running a higher operating system or use the web version of Facebook.

ishmael89 wrote:

I want to download Facebook on this iPhone 6 Plus

Facebook app requires iPhone 6s or newer.

Don’t like that? Contact Facebook.