How to add/modify new taxonomy terms in node edit form? (taxonomy type is not tag) For example, when adding/editing a node, if a needed taxonomy term(category) doesn't exist, then for the user with right permission, he/she can then add a new term without leaving the node editing form? The term should be hierarchical not like tags, for example the category of the content.

I believe I saw a module which can handle this type of thing by providing a button to create new taxo

Thanks!
May be you are looking for Taxonomy Other module ?