Private keys are your access to your bitcoins. Who ever knows your private keys(also known as seed) controls your bitcoins. It is not advised to share your private key with anyone. Also you should not keep it online, rather make a paper wallet or buy a hardware wallet like Nano-S or Trezor. Stay safe!
Thank you for your information .
And what about Electrum , is that safe to use that ?
What is watch only wallet ?
Second question : Can I create and use a password to access my wallet in Electrum ?
Watch only is same as read only. You'll be able to see all the addresses within the wallet but unable to spend those bitcoins.
And yes you can. Electrum supports pass protection. You need the pass to be able to send BTC ... without pass it's just read only (watch only) wallet