If you're running Windows 10, it should be a simple plug and play. You just download it. Open it once it's downloaded and that should be all you have to do. I don't know if you need to delete the old OS, but Microsoft would certainly know. Check their site. As a matter of fact, when you're downloading from them, they're system pretty much does everything for you, or tells you what you need to do next. Good luck and have a great day!
The Windows 11 upgrade via Windows update is not available. It says "Windows 11, version 22H2 is on its way to your device. There's nothing that requires your attention at the moment. Once the update is ready for your device, you'll see it available on this page." It has been saying this for many months now. Clicking on the "Learn more" link takes me to [URL] So it looks like there were issues but 2 have been resolved and the 3rd does not apply to my computer (as it only affects Intel 11 Gen CPUs and my i7-10510U is 10th Gen apparently). The Inspiron 7790 is listed in Dell's tested and compatible with Windows 11 list. Has anyone else with this computer successfully upgraded to Windows 11? And does anyone know the best way for me to proceed?  
How to upgrade to Windows 11 on Inspiron 7790 AIO?