Before you can place an order, an admin for your organization's account must enable it in the Account Settings. This gives all users within this organization the ability to order a Schematic Floor Plan.
Log in to Matterport Cloud and open Settings from the upper right menu.
Click on "Manage" under the "Account" tab. 
Under the "Product Settings" section, toggle the switches next to MatterPak Bundle, Google Street View, Schematic Floor Plans, Vrbo and HomeAway 360 Virtual Tour to enable any of these features - see below.
Return to the Space and go to Floor Plan under the Media tab. You will now see that the "Buy" option is available.
Measurement Units
If you often order Schematic Floor Plans in metric units, you can set metric to the account default.
Log in to Matterport Cloud and open Settings from the upper right menu.
Under the "Schematic Floor Plans" section, set the default measurement units - see below.
Set the default to metric or imperial as desired and click Update.