I want to summon a lightning bolt which can kill a player in one hit. That's all I want. I was trying to execute command, I think it is possible with it but I don't know how to do that, can you help me?
Commands cannot do anything about lightnings. They are instantaneous events, not entities (
@e[type=lightning_bolt] does not work). They are not even saved to file, closing and re-opening the world stops the ~1 second long animation.
The best thing you could do would be to summon lightnings via commands. In that case you can just do whatever you want at their location, like an instant damage effect or just summoning multiple lightnings.