It says I don’t have enough storage but I do.

Depending on the message it could be talking about your phone or your computer.

Resources:-

Update iphone

Update your iPhone or iPad - Apple Support

Learn how to update your iPhone via recent Macs here:-->

Update your iPhone, iPad or iPod touch with the Finder – Apple Support (UK)

or older Macs and PC here:-->

Update your iPhone, iPad or iPod touch with iTunes – Apple Support (UK)

 If the message is about the computer, you will need to move some data out to another drive.

How much storage do you have exactly? Settings ➡️ General ➡️ iPhone Storage