Now is exactly the wrong time to divide or move anything, assuming you are in the northern hemisphere (this is why we put locations/zones in our username).

Wait until fall.

Too hot and-or dry now. Could end up dividing and killing the little plants. Can you wait until Fall temps arrive?

I am wanting to divide and transplant in the fall, I am just trying to get as much information as I can right now. I believe it is a macrophylla based on all the images I have seen. I am in zone 7a.

Hydrangeas were not "designed" so we could divide them but still, many people use items like large spades to divide and are successful. There is, though, some risk in this practice and beware it's to hot for this now... Just be aware, specially if the shrub has sentimental value. In that case, propagate a few cuttings before dividing.

I moved a shrub once due to roofing work. When I settled it in its temp location, it broke in two and I ended with 2 plants without even trying to divide! Ha!

Do a forum search looking for words like divide.

Lots of mac crowns are very woody in nature, so a hand spade, other small tools or no tools at all are not recommended.

If dividing, try:

1. Dig up the plant
2. Shake some soil off the roots
3. Lay plant on its side
4. Use a sharp hatchet, large spade, hand saw or saws-all to split the crown into 2 or more parts.

You'll lose a few healthy stems and shoots in the process, but it won't matter in the long run. I personally don't recommend dividing hydrangeas that haven't grown to a 7-10 gallon root ball size.

Easiest time to do this is sometime in spring while the soil is still hydrated and somewhat loose, preferably toward the end of late freeze/frost spells if not after. Everything divided and transplanted by May.