To change a control, first you would need to select it in Design view. That’s easy: You'd just click it. Small black square handles would appear around the selected control.
Applying a change to several controls at once saves time and ensures that the change is applied to all of them in the same way.
To select several controls at once in Design view, you would hold down the SHIFT key and click each control you want. After looking at the handles to confirm the choices, you'd make your change. The controls remain selected after a change, in case you want to continue working with this selected group.
Tip You could also select a group of controls using the Select Objects button in the toolbox. You would click that button, click in the form, hold the mouse button down, and drag a rectangle around the controls you want. When you release the mouse button, handles appear to show your selection.