I don’t know if I should check on App Store and download electrum from there or I search on goggle?
Download it from the
official Electrum site also in the link hosseinimr93 posted above. Do not use google search for you not to see scam apps. While looking for apps, do not try anything Google at all.
You can see the correct link toelectrum website on Wikipedia, for example. Even driving the app's name into the google search. The probability of getting a phishing website is low here, but still, articles there are also written by people and moderated as well. So, for reliability, it will be better to check GPG signatures (information and instructions on this are available on the download page on Electrum website).