You'll receive $10 of Airtable credits for each person you invite to Airtable. You can invite people to use Airtable, and access an Airtable-referral link, from the Referrals and credits section of your Account page (Airtable.com/account, accessed from a laptop or desktop).

If you would like to invite someone to collaborate with you in Airtable, you will need to add them as a base or workspace collaborator (you will still receive Airtable credits when doing so).

From here, you can see the total number of credits you have and how you got those credits. You can also see every person you've invited, email out new invites, and find your referral link that you can use to get credits for referring new users.