A cryptocurrency airdrop is when a blockchain project distributes free tokens or coins to the crypto community to bring attention to their project.
To receive a cryptocurrency airdrop, typically the only requirement is that you have coins from the relevant currency in your wallet. Examples of this format of an airdrop are: BitcoinCash, Byteball, Stellar Lumens, or OmiseGo. These airdrops required you to prove you were the owner of the Bitcoin or Ethereum at a "certain time or snapshot of the blockchain".
Other smaller airdrops, which have become much more popular recently are when a cryptocurrency project distributes a predetermined amount of tokens to the community who signs up for the airdrop. Sometimes these need social media tasks whether it be follow them on different social media sites like FB, TWTR, TG, etc. As of recently, some of them require KYC (Know Your Customer) uploaded to receive them. Personally I never participate in these because I don't trust anyone asking for KYC for just an airdrop- it's ridiculous in my opinion.
To get started up on getting airdrops you will need some things to get started off:
MEW or Metamask wallet to store ERC-20 tokens. - a link for metamask's website can be found here: https://metamask.io/
WAVES platform wallet (only for some airdrops) https://wavesplatform.com/
Once you have this all set up you are ready to get started to sign up for some airdrops!
If you are looking to join a channel to get updated on airdrops and bounties you are free to join this channel
You can also sign up for Earn and get paid in BTC to sign up for their exclusive airdrops! Check out this article I wrote on it. You can sign up by clicking on the link in the article: https://steemit.com/crypto/@ansteadm/earn-a-new-way-for-businesses-to-communicate-and-users-to-make-money
If you have any questions feel free to ask me on TG (@ansteadm) or just post a comment on here and I'll be happy to get back to you!