i need to update my phone higher to get snapchat to work

No idea about that, since Snapchat requires iOS 11 or later and your iPhone seems to be already updated to iOS 15.

Please contact Snapchat about that.

Regards

Giulio

SnapChat requires iOS version 11 or higher.

Your Profile states that you have an iPhone XR with iOS version 15 installed. SnapChat app should have no problem working on your iPhone.

Axel F.