Sell IPhone

This is a user to user forum and Apple is not here. If you want to sell a phone, you will need to find a friend or family member who wants it. You can recycle them at an Apple Store. The iPhone X you can trade in for a new phone.

You can elect to send the phones to Apple apart of the Trade-In program. I would get the damaged device repaired prior to sending, as damage decreases the estimated trade-in value.

https://www.apple.com/shop/trade-in