If you are on a Mac or PC, you can simply click the account icon in the upper right side of any page to log out of your account.

If you are signed in to your account on a mobile device, click the three horizontal lines on the upper left side of your screen, scroll down to Account and click the arrow at the right of Account (be sure to click the arrow and not the word Account or you will be taken to the different sections of your account).

Once you click the arrow at the right of Account, scroll down to the Sign Out option (see screenshots below).