By default, the requirement of a shipping address is added as soon as you apply a delivery option to your reward.
You can always add the condition to require a phone number too. This will depend on your shipping provider requirements, who might ask for the phone number of the person receiving the reward, in case of any issue.
The option to require an address is possible in the case there is no shipping to your reward. We recommend to limit this to cases where it does make sense, like when issuing fiscal receipt if you are a non profit organization entitled to do so.