A web user with Admin access will have the ability to add new locations and products as well as change the default consumption rates.
When you create a new web user under Users Tab, you have the option to 'Restrict Web User access based on location'. Make sure it is tickled.
Click on 'Invite Web Users' and enter the email address for the new Web User. An email invite will be sent to you and the invited person. Once the invited person confirms and accepts invitation, he/she they will show up on the Web User page.
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