You can measure the distance between two points on your model. The results show you the distance in millimeters, and the Measurement Details window shows the distance, part names, and the X, Y, and Z axis deltas.
To save all active measurements, you can take a snapshot (or add a pin or markup to automatically take a snapshot). The measurement in each snapshot remains private until you add the snapshot to a story and share it with others. If you want collaborators to be able to create their own measurements, you need to open the story and edit the settings of that snapshot. Labels indicate which snapshots have measurement enabled.