DO NOT USE: this tag is for questions about the old "on hold" status, which used to occur for the first five days that a question is closed. That is no longer the case, so the tag only applies to old questions.
The "on hold" status was created to encourage users to edit and improve their question so that it could potentially become on-topic or otherwise acceptable for the site and be reopened. It was removed with the rollout of new post notices in December 2019, and now no longer appears anywhere on the network.
An "on hold" question is a closed question. To the system, there is absolutely no difference between the two. The "on hold" status is only applied for the first five days, after which the question automatically changes to a "closed" status.
This tag is explicitly for questions that only apply to questions while they are in the "on hold" state, and not for questions which are closed in general. If you are requesting that an "on hold" question be reopened (or unfrozen or whatever other word you want to use), you should still be using the reopen-closed tag.