The verified badge  appears next to a Facebook Page or account’s name in search and on the profile. It means Facebook has confirmed that an account is the authentic presence of the public figure, celebrity, or global brand it represents.

What are the requirements to apply for a verified badge?
Your page or account should have large no of followers in order to get blue tick or grey trick.

In addition to following Facebook’s terms of service, your account also needs to be:

*Authentic: Your account must represent a real person, registered business or entity.
*Unique: Your account must be the unique presence of the person or business it represents. Only one account per person or business may be verified, with exceptions for language-specific accounts. We don't verify general interest accounts (example: Puppy Memes).
*Complete: Your account must be active and have an about section, profile photo and at least one post.
*Notable: Your account must represent a well-known, often searched person, brand or entity. We review accounts that are featured in multiple news sources, and we don't consider paid or promotional content as sources for review.
Here's the link for verification: