if there are Parameters which show these values but not called Length & Width you can simply use the Formatting Edit to change the Column Heading Name.
If not you will need to create New Shared Parameters if they do not exist. There is lots of information in the Revit Help on how to do this.
One point to note is Length and Width are common parameters and it is advised you use a specific identifier to your Shared Parameter as it could result in 2 lengths and widths being included in other Schedules as these parameters are shared in nature..
Jay Colcombe
Autodesk Certified Instructor
Revit Architecture & Structure Certified Professional
AutoCAD Certified Professional
B.Sc. Hons Civil & Structural Engineering
If you find my post interesting, feel free to give a Kudo.
If it solves your problem, please click Accept to enhance the Forum.