Buddy

You can ask to be someone's friend by clicking on their penguin then clicking on the smiling face on the bottom left of the player card, say yes if you wish to ask to be their friend, say no if you have made a mistake or have dicided not to be their friend.

The penguin you asked can say yes or no to you asking to be their friend, if an envelope appears straight after you have asked them then their friend list is full.

(An envelope appears when they answer your request.)