In Dynamics v9, there are four custom form types that you can apply to your entities, all with a variety of features attached to them. In previous versions there were more types but these have been rolled into these four as part of their usage in Power Apps and the User-Unified Interface.
If you’re new to Dynamics here’s the quick primer on getting started.
The main form is strictly what it means, it’s the central form for accessing your entity in the web view across a variety of browsers. This version of the form has been around for years.
Quick Create Form
If you want to enable users to be able to quickly create records from other entities/places, you can use the Quick Create Forms. Quick Create Forms are that minimal set of information that can be used to create a new record. The only caveat to keep in mind when creating a Quick Create form is to enable the entity for “Quick Create” on the Entity properties page, otherwise your form will not be shown in the Quick Create options view.
Quick View Forms
Quick View Forms expand the lookup information associated with a child entity on a parent entity allowing you to view more than the name. This is great if you have a case that is linked to a product, but you don’t care about the product name, what you really want people to see is the code, or how many are left in stock. Quick View forms are a great way to solve the problem that most customers raise regarding “not having everyone in one place in Dynamics”.
Card View Forms
Card Views are meant to take advantage of the Customer Engagement Hub and show information in a card-like way using this new view.
If you are looking for more references on Form types, you can try here – hopefully this is continually updated, it references mobile which no longer exists.