You can do so in a couple of different ways:
-With the release of 1.207, the Jade Guardian Stone (the one that you talk to in order to send your residents out on dispatch missions) now has an option to "Give Gifts to Survivors", at the bottom of the list.
-The "View Continent Status" building has several options, including a "Settlement Residents" tab at the top of the list; click that, and you'll have a listing of all of the settlement's survivors. You can then click on an individual resident and select the "Give Gift to Character" tab.