The words much and many mean a lot of.
Use of much / many
In everyday English, we normally use much / many only in questions and negative clauses.
How much money have you got?
Carla does not have many friends.
In positive clauses with so, as or too, we also use much / many.
Carla has so many friends.
She has as many friends as Sue.
Kevin has too much money.
In all other positive clauses, however, we prefer expressions like a lot of/ lots of.
Carla has a lot of / lots of friends.
Kevin has a lot of / lots of money.
In formal texts, however, much / many are also common in positive clauses. This you will notice for example when you read English news.
Countable / Uncountable Nouns
In connection with much / many people often speak of countable nounsand uncountable nouns.
Countable nouns have a singular and a plural form. In plural, these nouns can be used with a number (that's why they are called 'countable nouns'). Countable nouns take many.
100 friends – many friends
Uncountable nouns can only be used in singular. These nouns cannot be used with a number (that's why they are called 'uncountable nouns'). Uncountable nouns take much.
100 money – much money
Note: Of course you can count money – but then you would name the currency and say that you have got 5 euro (but not „5 money“).