No elevated privileges are needed
UIPI is a security measure that "prevents processes with a lower "integrity level" (IL) from sending messages to higher IL processes". If your program does not have elevated privileges, you won't be able to use enigo is some situations. It won't be possible to use it with the task manager for example. Run your program as an admin, if you need to use enigo with processes with a higher "integrity level".
The user needs to grant the application the permission to access their Mac. Official instructions on how to do that can be found here. Enigo will check if the application has the needed permissions and ask the user to grant them if the permissions are missing. You can change this behavior with the settings when creating the Enigo struct.