You may want to add your members silently first, maybe even start communicating with them, and send the invitation later. Or maybe you want to prompt your members to fill out their profile again. You can do that by inviting your existing members to register.

You'll do the following:

1. Check and customize your default invitation text
2. Navigate to the Member Database
3. Select the members you want to invite to register
4. Click Re-send invite
5. Recheck your invitation text
6. Option to edit the text for only this process without saving into the template, or you can make changes and save the template
7. Send
8. Your members will get an email with your text and a large button to click on that will take them to the registration form
9. Existing data will be pre-populated on the form

Here are more details with screenshots:

Customize your default invitation text

You can customize your message before inviting your members in the Membership Emails section in your Group Settings area.

Invite your members to register and fill out their profile

If you've already added your members and you want to invite them after you've set up your group, go to your Member Database and select all or specific members you want to invite. 

On the bottom left, click the Re-send Invite button to review your invitation text first, before you send it.

Customize the text if needed then click Send Invitation:

The invitation message looks like this for your members in their inbox: