Invite code generation
If you want to leave invite codes enabled on your installation, you'll need to know how to generate them for users! There are a few ways you can do it.
Single-user grants
Give a user the 'payments' priv and visit the Admin Console (/admin/console). The command to generate invites is:
make_invites username number "reason"
For instance:
make_invites system 5 "to create dev accounts"
Multiple user grants
To give out invites to all users (who match certain criteria), give a user the 'payments' priv and visit the invite codes distribution page at admin/invites/distribute.bml. You'll need to have the 'distribute-invites" TheSchwartz worker running for this to work.
By request
While logged in as the user you want to make the invites for, visit the Invite Someone page at /manage/circle/invite.bml and click the link to request more invites. Then give yourself the 'payments' priv and visit the invite codes requests page at admin/invites/requests.bml. You'll see the request there and can choose how many invite codes to grant.