For a 3D static magnetic analysis using the scalar formulation, you can apply the following loads:
Constraints - Scalar potential (MAG)
Forces - Magnetic flux (FLUX)
Surface loads - Maxwell surfaces (MXWF)
Body loads - Virtual displacement
Current (via SOURC36 element type)
To apply constraint-body loads, use the commands listed in Loading Options for 2D Static Magnetic Analysis. You prescribe current sources by defining SOURC36 elements.