GPG Suite Custom Install
Sometime users do not want or need all components from GPG Suite. During the install process you can opt for a custom installation.
Follow the installer and once you arrive at step 4 "Installation Type" click the "Customize" button.
The Custom Install allows you to de-select components as desired.
Note: This screenshot was created on macOS 10.13 with GPG Suite 2018.4 so GPG Mail is listed twice, once for macOS 10.13 High Sierra and for macOS 10.14 Mojave.
GPG Mail FAQ
GPG Keychain FAQ
GPG Services FAQ