How to get storage to update my phone

J_c35 wrote:

how do I update my iPhone 13 to the iOS 18 when I don’t even have storage I have plants of iCloud storage but no iPhone storage so I’m wondering how to fix this

The amount of iCloud storage you have has no effect on how much local storage you have on your phone.

See here:

What's the difference between device storage and iCloud storage? - Apple Support

And second, unless this is a spare phone, you should not be installing beta software. Beta software, by definition, is not complete and has problems. Apple releases beta software so that developers can test it. If you are not a developer and you only have one phone, it's a bad idea.

First, iOS 18 is in beta and it is suggested by Apple not to install it on a machine that you depend on.

If you go to Settings>General>About> and look down till you see Capacity, you will see how much memory you have on you iPhone and right below it what is Available.