You can gift Bronze boxes to your friends daily by tapping on Social > Friends. Once you are on the Friends page, you'll see a gift button right beside their name. Tapping it will send a bronze gift box to them. Tapping the "Gift All" button will send gift boxes to the first 10 on your friend's list. Remember that you can only send and receive a maximum of 10 gifts per day. If you wanted to manually gift your friend, you can tap the gift button beside their names instead.