I want to know that is electrum safe or not?
Both PC and Android client.
Yes. For what it is worth, I use it extensively. I don't know of any security audit done but it has been around for a good amount of time without any major issues being discovered.
And the simplicity of being able to recover your wallet from your 12 word seed is very powerful in helping users avoid common mistakes.
I am mostly talking about windows and linux clients. The android is somewhat more experimental. I've used it but I wouldn't store a lot of bitcoin there.