You can access the Account Verification flow from either Settings or on your Profile. 

In Settings, you tap on “Verify Profile”, on your profile, you will tap on the shield icon next to your age/birthday that has the badge on it, indicating a call-to action:

Once you select either of these options, you will then be prompted to copy a pose that is provided. Please be sure that the pose matches the photo you have been provided, and that we can see your face clearly as this could cause us to ask for another photo from you if the photo does not match.

After submitting the photo, you will receive an alert that says you're pending verification. Once you exit out of this view, you will see that the icon is in pending view mode (shown in a light color). If you are approved, then you will see the icon show clearly on your profile, account will say verified in settings and you will receive a message stating that you are verified.