Running software that hasn’t been signed and notarized may expose your computer and personal information to malware that can harm your Mac or compromise your privacy. If you’re certain that an app you want to install is from a trustworthy source and hasn’t been tampered with, you can temporarily override your Mac security settings to open it.
If you still want to open an app for which the developer cannot be verified, open System Preferences.*
Go to Security & Privacy. Click the Open Anyway button in the General pane to confirm your intent to open or install the app.
The warning prompt reappears, and if you're absolutely sure you want to open the app anyway, you can click Open.
The app is now saved as an exception to your security settings, and you can open it in the future by double-clicking it, just as you can any authorized app.