Airdrop is a new coin that they need to endorse so that if their ICO will be successful, their coins will going to have a value with the exchangers. 1st, you need to join in a telegram that will update your if there is a new airdrop that you can join, or here in the forum, you can see it in the altcoin section. After that, you need to fill up their form and follow the instruction that is given so you will receive a token from them once it is successful. Not all the time we can receive a token once we join in the Airdrop it will always depend.