Cant update to iOS 13

See the section regarding updating with the computer in this support document, Update your iPhone, iPad, or iPod touch - Apple Support It mentions what to do when you have Catalina. Catalina does not use iTunes, it uses Finder.

mhattonmd wrote:

I can't find a version of iTunes to install that works with Catalina

There is no iTunes for Catalina. You use the Finder.

https://support.apple.com/en-us/HT204204

Download and install iTunes on a computer (Mac preferred) and do the update with that instead.

What happens when you try to update? Are you getting an error message? If so, what, exactly, does it say?

Exactly. Catalina is a whole other experience.

(to put it mildly)

But do persist, updates thru the more robust resources of a computer are less prone to failure.

Please verify the model number at Settings - General - About - Model = ???