1999 Ford Expedition starter

Then there are three bolts that hold the starter to the bell housing. The bottom two are easy to reach. One of them also has a ground connector attached to it. The top bolt is more difficult to reach, and you cannot see it from underneath the truck. If you use enough socket extensions to get the head of your ratchet past the end of the starter motor, you can guide the socket onto the top bolt head with your fingers by feel.
I found it best to remove the top, difficult bolt first, and then move on to the next bolt, and finish with the easiest. This lets you hold the weight of the starter while removing the last bolt. If you do it the other way around, the starter 'sags' on the top bolt and complicates removing it.