Sorry if I misunderstand but I'll assume you mean the difference between tarot and oracle cards.
Tarot is a set system of 78 cards divided into major and minor arcana. The minor arcana are then divided in to suits. Each card has a designated (although fluid) meaning throughout every deck.

There are different schools/systems of tarot, eg. Smith Waite system, Marseille system and Thoth system. Almost every tarot deck will fit within one of these systems (note - not all) and once the basics of a specific system is learned then it's possible to read different decks within that system.

Lenormand is also a set system of 36 cards where each card has set meanings. Every Lenormand deck has the same meanings even if the artwork varies.

Oracle cards are decks of cards where every deck is different. Usually they have a theme and have different meanings. No two oracle decks are the same system, every one will carry different meanings.

Tarot and Lenormand can be learned through many resources, oracle cards tend to come with a specific guidebook that does not work with another deck.

Hope I've understood yoyr question and that this helps.