By default, Vectorworks no longer includes the Cut 2D and Cut 3D section commands as part of the workspace, however these commands are still available to you through the Workspace Editor.
Go to Tools > Workspaces > Workspace Editor and select the Menus tab. On the left, expand "All Menus" and scroll down to the "Cut 2D" and "Cut 3D" commands.
Expand the menu on the right hand side that you wish to include these commands in, (For this example we place them under the Model menu.) then click and drag the two tools from the left to where you wish them to be located on the right.
After doing so, click OK and you will see your commands in the menu you placed them in.
Edited by JimW