To get the extra name and room number fields to show when creating an order follow the steps in this guide.
Globally
To enable it globally go to Settings -> Business Settings -> System Settings
Click on the Company Settings Tab
Look for the setting "Enable Extra Information Fields"
Now when you create an order you'll be to see these fields and add data to them
Specific Customer or Group
To enable it for a specific customer or group. First search for the customer/group
Click on the customer's name
If the group is a hotel you can click on "Admin" and then change the account type to "Hotel"
If it's for a specific customer and isn't a hotel you can click on "Settings -> "Company Settings" -> look for the setting "Enable Extra Information Fields" and enable it