The 'Discipline' picklist is a part of ProjectWise Forms 'Design Task' which can be edited to add/remove values.
Please follow the steps given below to add more values to the Disciplines list:
Step 1: Click on ‘Dashboard’ on the tiles present on the left side of the screen.
Step 2: Click on Settings wheel on the top right corner of the screen.
Step 3: Click on ‘Task’. Select ‘Design Task’. Change Status to ‘Draft’. Click on Edit (pencil icon)
Step 4: Double click on ‘Discipline’ & edit the ‘Items List’ to add more values to the picklist.
Once done, please save the changes and create a design task again.