Main types of bicycles are road, mountain, commuter/comfort and fitness bikes. There are more specific types and other names for bike types within that, such as urban bikes (same as commuter bikes), cruiser bikes, dual-sport bikes, hybrid bikes, fixed-gear bikes, cyclo-cross bikes, adventure road bikes (aka all-road bikes, gravel bikes), road bikes, touring bikes and specialty bikes, like BMX.
Friction gear systems are a lot simpler to adjust, because the movement of the derailer cable can be modulated as you ride, every time you change the gear- they require less cycle maintenance. Modern index shifting systems are a little more complicated because each ‘click’ must release the exact right amount of cable to allow the derailer to move the correct distance to move the chain from one gear to another. Setting up and adjusting a derailer is not difficult and requires only basic tools, but there is a methodical procedure to follow.