Invitations are a way you can make sure the hard work you do for a client is noticed. It allows you to create a connection to the agent and all of your farms and areas you save for them will be accessible in their own dashboard.
If your client does not accept their login, your invitation will expire. You cannot simply "invite all the agents" first blindly as it would be jarring for an agent to get an unsolicited invitation, and they would be less likely to accept.
If your client is having trouble receiving the invitation to their email, you can download an invite link from the My Invitations section in your Partner Dashboard and send direct via your own email to the client.
When a client you invite refers a friend via our referral program, the new agent will also be invited under you.