Depends on the rear hub as to what you can do.
If it’s a standard Shimano hub you can go 11 speed and to change to 12 speed would need a microspline freehub. A lot of hubs are now changeable though but just depends on what you have currently.
I’m guessing, as it’s Shimano now, this ill be the case so would just be a case of picking what level you want to go to.
You’d need, minimum, rear mech/shifter/chain/cassette and a single ring for the front.
Looking at the spec the cranks are 104mm BCD so that’s the ring you’d need to get.
edit: looking at the wheels I’d say you wouldn’t be able to go 12 speed so 11 would be the way to go unless you can get a SRAM freehub then that opens up the SRAM options.