I don’t know if I should check on App Store and download electrum from there or I search on goggle?
Since you referred to App Store, I guess you are looking for IOS version of electrum. If that's the case, note that electrum isn't available for IOS.
You can visit
the official website and download electrum for Windows, macOS and Android.
Do not forget to verify your download. Below is the guide provided by DireWolfM14 on how to verify your download.
[GUIDE] How to Safely Download and Verify Electrum [Guide]My PC is not available for use at the Moment so Since I can’t get electrum on IOS. Which app can I get on IOS ?