Does Danzo use a curse mark? I totally understand what the Curse Mark is about, but I never knew that Danzo uses them like Orochimaru does. Not until some of the more recent episodes. I didn't even know The Foundation had access to such jutsu.

I always thought that the Curse Mark was something that only Orochimaru uses, and that Danzo used a "Sealing Jutsu" on Foundation Members. So who actually created the Curse Mark?
The curse mark that you are referring to in context to Danzo is the Root Paralysis Juinjutsu which members of the root term it as &quot;curse mark&quot;. It does not refer to the same curse mark that Orochimaru uses.

This cursed seal is given to all members of the Anbu subgroup Root by
Danzō Shimura, to ensure no information about Danzō or the
organisation falls into the wrong hands. After Danzō died, the seals
disappeared from all the Root members.
When the wearer of this cursed seal speaks about anything
incriminating related to Danzō or Root, their entire body will be
paralysed, taking away their ability to speak or move. It is applied
to the tongue and takes the shape of three solid lines and two broken
lines from the back of the tongue to the tip.
The seal can also be applied during combat, and can secretly be placed
on the opponent's body. When the user activates it, the curse seal's
marks spread around the opponent's body, paralysing them. However, one
can break free from the seal with a strong enough release of chakra.



Sai had mentioned about it,

Sai said that he could not, as the cursed seal Danzō had placed on
his tongue prevented him from revealing anything about Root. Sakura
remarked it was cruel, but Sai explained that it was for the best
since Root had done a number of questionable things to protect the
village.

Source

The curse mark that Orochimaru uses is called Orochimaru's Juinjutsu.

Orochimaru's Juinjutsu are the cursed seals that were an often-used
technique of Orochimaru in the series.


So as to the question Does Danzo use a curse mark the answer is yes, its called the Root Paralysis Jutsu.
And to the question who actually created the cursed mark the answer is, both Orochimaru and Danzo created their own cursed seals.