You can do it couple ways:
1- You can manually set each destination and give it a name like work, school etc.
2- You can also do this while you are at the location. you can use your current location and add it to your favorites.
Here is the BEST part. Waze could recognize your location and suggest the next route.
You need to make sure you enable (TURN ON) this option whithin the Waze's settings.
Waze: SETTINGS>ADVANCED>AUTO LEARN ROUTES TO FREQUENT DESTINATIONS.