Crypto mining is the validation of transactions. This is the process that makes crypto currency work properly. Most mining today runs on ASICS or Mining Rigs to perform this task. The process is slightly different per crypto currency, and not all of the crypto currencies can be mined.
Cryptocurrency mining includes two functions, namely: adding transactions to the blockchain (securing and verifying) and also releasing new currency. Trying to not get too complex; Miners are essentially solving a complex mathematical task to produce the transaction records this is also known as “Hashing”, this hashing occurs millions of times a second and most of the hashes are incorrect, only the correct hashes get added to the block.
For the home miner, most Crypto, it is generally deemed to be non-profitable. However one coin seems to buck the trend which is monero as it is thought to be ASIC resistant and favours CPU's over GPUs. It can even be mined directly in your browser!
There are several ways to mine, the most simple is with your home PC using it's CPU and Graphics card. Next up from that is a Mining Rig, this is really just a home PC with multiple graphics cards. Finally you have ASICS, these are chips specifically designed with one thing in mind, to mine, so they tend to be the most powerful and efficient way to mine for Crypto.
Electricity, Noise and Heat
One thing to consider, mining consumes alot of electricity, so factor that in when you are making any profit calculations.
Something else people tend to forget, it's the amount of noise. A single Bitcoin ASIC might make as much noise as 80dB, so not real good if you have to be in the same room.
Also mining tends to make alot of heat, so in the winter, you may not need to put your heating on, but in the summer you could have a real problem keeping those miners cool!