I had to change the headlamp assembly on a 1995 Ford Taurus GL, and it turned out to be a little trickier than I thought.

(I purchased the new assembly at rockauto.com for about $42 including delivery. The label on the box says it also fits the 1994 Taurus GL, and 1992 & 1993 Taurus L, GL, LX & SE, but double check on a couple other sites, because rockauto doesn't show some of those models as being applicable to these particular headlamp assemblies. If you buy both (which I suggest, for looks) Amazon has them even cheaper. And Car-Part.com will probably turn up a used one for even less.)

The tricky part is due to a combination retaining & aiming clip.

It can be difficult to see how it works, and therefore, hard to remove. There are 3 of them on the assembly. I did not receive new clips with the headlamp assembly, but I did not need them in the end, even though a couple of them looked very rusty.

These clips have two extensions that lock into indents on the plastic aiming assemblies. That requires you to bend those extensions outward while pulling up (or levering up with a screwdriver, if you can manage it) on the top of the clip.

A little penetrating oil (e.g. WD-40) might help, especially if the clips are rusty.

For the two clips on the upper assembly, I found that I could use a flat-head screwdriver to apply leverage pressure while bending the extensions out, one at a time, with a very small screwdriver.

For the clip on the lower assembly, it was really tricky, but a small pulling tool (like a forceps with the tips bent inward at 90 degrees or more) was able to apply sufficient pull on the clip while bending out the extensions, one at a time. It was difficult and took several minutes to work it off.

(If, after installing the new assembly, you find that you need to adjust the aim, the upper aiming screw may suffice. If not, you may get away with bending down the body trim below the headlamp assembly to access the lower aiming screw. If you decide you must remove the trim, it would probably require many new, plastic trim-locking tabs, which, in my experience, do not tend to survive the removal process. But they are not very expensive. A Haynes repair manual would probably be a good investment for advice there.
** EVEN BETTER: you may be able to adjust the lower aiming screw from the back end with a specialized tool that should be available at most car-parts suppliers, and would probably be so much easier than removing/replacing the trim that it would be worth the investment, easily.
**** MAYBE EVEN BETTER THAN THAT: I was able to adjust the lower aiming screw from the back end with a miniature ratchet wrench and a 4mm hex socket that I already had, but I would guess not many folks have those tools.)