How can I update my software to iOS13

How can I update my software to iOS13?

I suspect you probably can't. Look here for the hardware requirements for iOS 13. Does your (unnamed) device appear on this list? If not, then it is incapable of supporting iOS 13. If it is upgradeable, iOS 13 is no longer offered - instead you will see an upgrade notice for iOS 15, the current system. This will be in Settings > General > Software Update

how can I move everything from my phone storage to iCloud without using files?

What is it you want on iCloud that isn't already there? Moving suggests storing remotely while removing locally. iCloud does not work that way, it is a syncing service. What is added, edited or removed on iCloud also is added, edited or removed on your device(s). You'll find most of the content of your device is already shared with iCloud: Apps are sourced and reinstalled from the cloud, your photos are or can be synced with iCloud, your iCloud email comes from iCloud, some apps share their data with iCloud for syncing to other devices you may have.