A Coin or Token Airdrop is the process when a Crypto/Blockchain project distributes it’s cryptocurrency tokens to those participating wallet holders.
OR
It is a procedure of distributing new tokens/coins by awarding them in a certain proportion to existing holders of a particular blockchain currency.

Why Free Crypto Airdrop

1-Endowment Effect:
People pay more attention to things merely because they own them.
2-Token Economics:
Wide-spread of token holders is better than one man holding all the tokens
3-For Marketing Purposes.
4-To create a community

The Tools You’ll Most Likely Need to Participate in Free Airdrops

1-An Ethereum Wallet(Must be ACTIVE)
2-Telegram Account
3-Twitter Account
4-Email address
5-Facebook Id

How To Get Your Free Airdropped Crypto?

1-Join an active crypto community
2-There are some services and websites through which you can get regular updates about airdrops here are some examples:
airdropalert.com
airdropking.io/
oinairdrops.com/