Align

Line objects up on an axis.

Align snaps the selected objects to a shared minimum, center, or maximum along an axis, so edges or centers line up exactly. By default they line up within the bounds of the whole selection. Switch Align to to Key part to line everything up to one part that stays where it is instead: the key is the part you selected first, and while Key part is on, clicking another selected part makes that one the key. A box marks the key.

1. Select two or more objects.
2. Open Arrange → Align.
3. Pick an axis and min / center / max.