The consumer unit(commonly known as the fuse box) has a main isolating switch which turns all the power off.
Additionally you will see a number of fuse carriers, or in newer units circuit breakers.
In older houses which probably haven't been rewired for a long time you may have a consumer unit with pull out fuse carriers which either have a wire fuse which you change with fuse wire, or a cartridge fuse which slots in place.
If a fuse blows you will need to replace these. Make sure you switch off the main isolating switch on the consumer unit.
NB IT IS ESSENTIAL FOR THE SAFE WORKING OF YOUR HOUSEHOLD WIRING THAT YOU USE THE CORRECT SIZE FUSE OR FUSE WIRE.