You can add additional users to Float using the following steps.
From your Float dashboard, select the 'x users' option against the relevant company as shown here.
Alternatively, from the main cash flow page, click on the drop down beside the company name and then the Manage users option
Select 'Invite new user'
Enter the email address of the person you would like to invite. Followed by the role they should be given (roles explained here)
3. Click 'Invite' to send the invite.
The new user will then be sent an email invitation to access Float, all done. If you're looking to remove a user, find out how here.