Proof of Work (PoW) is a mechanism where the right to add blocks goes to whoever first solves a computationally hard task. Bitcoin and many other coins use PoW. Mining consumes electricity and hardware, but network security is tied to real cost.
Proof of Stake (PoS) uses a “stake” - locked coins - instead of computation. Participants with a larger share and/or longer lock-up more often get to propose blocks. Energy use is minimal, but critics point to centralisation among large holders and the lack of “external” cost for security.
Classic mining remains the basis of Bitcoin and several other networks; staking is an alternative in other projects, not a replacement for BTC mining.