It really depends on how you’re using this. Is this a front end form or an admin form? Is this something that the “Users” are entering on the front then? Is this something you’re doing in the admin?
The easiest solution might be “Create Terms” setting for the taxonomy field, but this just let’s you create the term and set the name, it does not let you edit the description and will not let you edit anything else about the term.
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