Click on your profile in the upper right corner.
Click "settings".
Click "investor settings" and then "user management".
Click the "+" button.
Click "invite users".
Select role (you will probably want to select "user") and then click "next".
Select the fund you want to invite the person/user to and then click "next".
Type in the user's e-mail address and then click "invite user". You may invite several users at a time by typing in multiple e-mail addresses separated by comma.
Success! The user has now been invited.
The invitation is active for seven (7) days. If the invitation does not get activated within that timeframe the invitation must be sent again.