When should I evolve my Kadabra?

Abra evolves to kadabra when level 16 is reached. So it’s really whatever you want to do. Its level has to reach 16 to evolve into alakazam or 18 for drowzee. Go ahead and evolve it as soon as you’re able to!

What level should I evolve Kadabra into alakazam?

Kadabra will evolve into alakazam immediately following the trade, at which point you just need to trade back. It evolves from abra starting at level 16 and evolves into alakazam when traded. However, kadabra and alakazam learn the exact same moves, so that’s not.