To begin with, you should create your own bleach solution, mixing together one part bleach with 10 parts water in a spray bottle for ease of use.
Then, you can tackle the issue in your shower enclosure by soaking the mould and mildew on the shower floor and tiled walls with the solution. Take particular care to tend to visible mould that has appeared on lightly coloured caulk or grout.
Allow the solution to sit on the affected area for at least five minutes.