Use the Disps tools on the Structure ribbon to apply enforced displacements and displacement constraints.

Before running an analysis or optimization, you need to define at least one load case, which is a set of loads, displacements, accelerations, and/or temperatures that act on your model. You may also want to create multiple load cases with different loads and displacements to understand how this impacts the results of an analysis or optimization.

As a general rule, displacements should be applied to non-design spaces rather than design spaces. You can also move displacements away from your model and connect them to geometry features using connectors.