If you’re an Android user you can either, tap 
at the bottom bar, tap your profile photo in the upper right hand corner, or drag out the left sidebar. In the new page or sidebar, click your profile photo, then tap Edit profile in the upper right corner. Press the Logout button, and you’re good to go.
If you’re an iOS user, go to the Me tab in the app and click your profile photo. Then, tap "Edit Profile" in the upper right corner and press the "Logout" button.
If you’re using our webpage, click your profile photo in the upper right corner and choose "Sign out."