Social
Alerts & the app
Alerts on your phone, the game as an app.
Settings → Alerts: turn them on for this device, pick the kinds, send a test. They only come while you are not playing.
Expeditions and the mine
Potions in the belt
Arena
Mail and trades
Guild
Daily reward
The realm
Invited friends
As an app
Android, computer
The browser's “Install”.
iPhone
Share → Add to Home Screen – needed for alerts.