KeePassXC AutoType does not work with Wayland.
To switch into Xorg follow the steps above by @Ponce-De-Leon, but just to clarify something: you need to first login to your user account and then logout, to be able to see this button (here, "Zorin Desktop" means using Wayland).
If you prefer to continue using Wayland you can also install the KeePassXC browser extension and enable integration. But note that this only works for browsers and will not work with other windows.