Bois is for I and you (Je bois and tu bois). Boit is for he/she drinks (Elle boit).
From the screen where the sentence was presented to you, click on the verb (bois) and then click on Conjugate. It will show you all the forms used in conjugating the verb. You may also open a page in your browser, such as http://www.conjugation-fr.com/conjugate.php?verb=boire