Some English help websites don't even mention it when they explain Moods. Grammar-Monster.com, for example, has it down as "the infinitive form of a verb" on a completely different [page](https://www.grammar-monster.com/glossary/infinitive_form.htm) and does not include it on the page explaining [Mood](https://www.grammar-monster.com/glossary/mood.htm).
Other English help websites, however, do list it as a mood, like this [website](http://www.english-for-students.com/the-infinitive-mood-of-verbs.html) does.

So, is it a mood or isn't it? I am so confused. 
 (And be gentle in whatever technical grammarians' jargon you have to use in your answer because I know next to nothing on English Grammar.)