Why miners solve a puzzle in proof of work I am new to block chain, In PoW, I know a puzzle is given to the miners to solve and the miner who solve the puzzle and find the nonce first will create the block.

But I don't understand why there is such a mechanism like solving a puzzle and finding the first one to create the block, is this puzzle is used to find the miner with more computational power? so he can create the block quickly?
No, the time spent creating a block is tiny and even a simple cell phone could make it in a few microseconds, if we leave aside the puzzle-solving time.

The purpose of mining is not to find who has the most computational power, but to make those miners with lots of computational power to 'waste' electricity. I say 'waste' but it's not actually wasted because mining itself is important. I mean in the sense that, to create an artificially scarce resource - bitcoin - mining was designed to take advantage of naturally scarce resources: electricity and computer time.