Safe to turn off power by removing a plug fuse indefinitely?
In the case of a wire fuse, the fuse wire may be removed before replacing the fuse carrier.
Likewise with a cartridge fuse.
Otherwise the outgoing wire from the fuse holder would be required to be disconnected.
The work would require the mains isolator to be switched off, the main fuses to be removed to ensure that the circuit being handled is not live and the off status confirmed using a tester.
Since you do not have prior experience working on mains wiring, it would be advisable to  have a certified electrician to carry out the work.