Tag questions would be something like:
He read this book, didn't he?
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In English, tag questions have a specific name because of their particular construction, that you must learn (including some particular cases, such as "I am..., aren't I?"). In Spanish you don't need to learn any specific construction, as tag questions are simply like this:
Él se ha leído este libro, ¿verdad?
Él se ha leído este libro, ¿no?
Él se ha leído este libro, ¿cierto?
Being the first option the most common one, at least in Spain. If you want, you can say that they are preguntas de confirmación. In the Nueva gramática española you can find these constructions as apéndices confirmativos, apéndices interrogativos or muletillas interrogativas among other names, as written in paragraph 42.8a.
I've always used a question tag by just saying: ¿o no?
What's easier in Spanish language is that you don't need to refer to the grammar structure when it comes to using a tag.
Unlike English, you need to say Doesn't he? Didn't he? Wouldn't he?