The difference of 많아 and 많이
I've seen both of these terms used, and I'm curious as to when to use which one in which context?

Question

Answer

많-아 is conjugated form from 많다. 많다 means to be a large number of or a large amount of.

많이 is a derivative of 많다.

Answer

많아 is an adjective/descriptive verb. It's usually found at the end of the sentence e.g. 사람이 많아 (there are many people)

많이 is an adverb, so a verb/adjective has to follow. E.g. 많이 했어 (I/you did a lot)

Answer

많아(요) is the conjugated form of the descriptive verb (adjective) 많다. 많이 is the adverb form.