The Fixed Point feature () can be added from the model tree under Component>Definitions using the Shape Optimization context menu. It is only available in 2D and includes no specific settings so you only need to specify the selection of points where it should be valid in the Point Selection section.

The feature fixes points in place, but keep in mind that boundaries are automatically fixed, if they are not associated with a Polynomial Boundary, Free Shape Boundary, Free Shape Shell, or Symmetry/Roller feature.