Hello, this is Emily.
Before you upgrade from Windows 10 to 11, it is best that you run the PC health check app to make sure your computer meets the requirement. https://support.microsoft.com/en-us/windows/how... If it doesn't, I wouldn't recommend upgrading. If it does, it should be safe to upgrade to Windows 11. The upgrade process is supposed to be seemless and won't cause data loss. With that being said, everyone's computer is different and the usage history is different, meaning computer's current health is not all equal. If you want to be extra cautious about it, it is always a good idea to back up important personal files before you do that just in case.
Also keep in mind, after you upgrade to Windows 11, if you don't like it, you can roll back to Windows 10, but you must do it within 10 days.