If you are lucky enough to have received a detailed design brief which lists all the required rooms in your project, you may want to load these into your project to save time entering them manually. Within Revit, these become ‘unplaced rooms’. When you go to place a room, you will have the option of placing a new room or an existing unplaced room if they have already been created.
To automate the creation of these rooms en mass, you can use the ‘Room.CreateUnplaced‘ node as part of the Parametric Monkey Dynamo package. Simply create a list of room names to be created and wire it up as shown.
If you don’t want to do a bunch of syntax modifications in a code block to create your list, you can also use the ‘Excel.ReadFromFile’ node to import the list from an Excel spreadsheet.

Before running the script, ensure you are in a standard view (plan, 3D, etc.) and not a schedule or sheet view. Otherwise, Dynamo will be unable to create the rooms. Also, you may want to set Dynamo to run under ‘Manual’ as opposed to ‘Automatic’ so that you don’t get duplicate rooms. If you need the room number as well, you may want to check out the ‘Room.UnplacedByNameAndNumber‘ node from Clockwork Dynamo package which works in a very similar way.