With 23w12a comes signs that can be both be edited and also can contain text on the "back" side of the sign. However, the same cannot be done with hanging signs.
Linked issues
duplicates 1
Comments 5
If holding a hanging sign, I cannot edit a hanging sign. "Use" does nothing at all.
If holding a normal sign, "use" on a hanging sign places a normal sign instead of editing the hanging sign.
If holding nothing, editing the front/back of a hanging sign works the same as a normal sign.
Then this is MC-261223. While older, this is a lot more vague and misleading.
I'm forward-resolving this issue as a duplicate of MC-261223, as that ticket is more detailed.
Unconfirmed.
I can edit the back of the sign. Perhaps OP means they can't edit the back of a hanging sign while holding a placeable block: see MC-261223