You can add a Phase subnode to nodes which define a load in order to prescribe the phase angle in a frequency domain analysis.

Together these define a harmonic load, for which the amplitude and phase shift can vary with the excitation frequency, f:

Add the phase load Fph for harmonic loads. Enter the phase for each component of the load in the corresponding fields.

 Truss>Edge Load>Phase
 Truss>Point Load>Phase

Physics tab with Edge Load or Point Load node selected in the model tree:
Attributes>Phase