To edit a user's permissions you must be an admin for the respective company. From here you will select the "Settings & Users" section from the company as shown below.
Once you click into the "Settings & Users" section you will immediately be directed to all of the users associated with your company (shown above).
From here, you will be able to click on a user's name and will be able to edit their permissions as shown below:
A user can have any of the following permission levels:
Admin — Can access and edit data, dashboards, updates and company settings.
Editor — Can access and edit data, dashboards, updates and assets. No access to company settings.
Viewer — Can access and view data, dashboards, updates and assets. No access to company settings.