¿Cuál es la diferencia entre Im y In ?Puedes dar oraciones como ejemplo.

“Im” and “in” both mean “in” in the English language.
It‘s just that “im” is mainly used for masculine nouns that have the article “der” in front of them, but “im” also is written in front of neutral nouns that have the article “das” before them.
“In” stands in front of feminine nouns that have “die” in front of them.
So when you want to say in the house (das Haus), in the wardrobe (der Kleiderschrank) or in the bag (die Tasche) it would be something like this:

Das Kind ist im Haus./Das Kind ist in dem Haus.
The child is in the house.

Im Kleiderschrank sind viele schöne Kleider./In dem Kleiderschrank sind viele schöne Kleider.
In the wardrobe are a lot of beautiful dresses.

Das Handy liegt in der Tasche.
The mobile phone is in the bag.

“Im” and “in dem” is the same by the way, which means you can use both. We germans are just often pretty lazy when it comes to talking so we tend to shorten words up.
“In der” is just always written together and tbh I don’t know exactly why as well xD
Nevertheless I hope you understood it now :D