You have three ways to invite a teacher, parent or a student:
Bulk invite (many community members at once)
Go to Admin → Schools → Send Invites → Start Invites.
This sends invitations to all pending accounts at once.Invite immediately when creating the school admin account, parent account, teacher account or student account
When adding the account, check the welcome email box during setup. That sends the invitation right away to that parent.Send a single invite later
After the account has been created, you can choose when to invite a parent. Open the account's management → Management menu → Send Invitation Email → confirm.
This lets you invite just that one user anytime.
So: bulk for many (excludes school admins), welcome email for immediate one-time invite, and the management menu for sending a single invite later.