I can’t find the update in my storage

Well, as you didn't say that it says Update Requested. I tried to read your mind about what you meant to say, and I did a poor job of it. A stray update file would not result in a message that says Update Requested. A stray update file would display "You have the latest version"

If it says Update Requested for more than a minute or two here are some possible reasons:

• You aren't connected to Wi-Fi
• The phone is in low power mode
• The phone is not charged to at least 50%
• The phone is not plugged in
• You have Update Automatically turned on, and you didn't leave it plugged in and connected to Wi-Fi overnight (you can turn it off and update manually)
• There isn't enough storage available to download the installer (which is larger than the installed iOS 13). You should have at least 3 GB available.

If fixing all of the above doesn't resolve the problem you can update using your computer. See that section in this link-->Update your iPhone, iPad, or iPod touch - Apple Support

Go to Settings/General/iPhone Storage. If it isn't there then it's already deleted. If you are having trouble updating it may be because you had a beta version of iOS 12 on your phone. If that is the case go To Settings/General and scroll to the bottom. If you see a folder called Profiles (just below VPN) open it, tap on the beta profile and delete it. Then restart your phone and it should update if you go to Settings/General/Software update.