What is the difference between a canvas app and a model-driven app?

Power Apps has two main types, and they solve different problems. You often don't realize you've chosen the wrong one until the app is half finished.

Canvas app

You position the elements yourself, as in presentation software. This gives you full control over the appearance and is well suited to simple tasks with only a few screens—typically something intended for mobile use in the field. The trade-off is that everything has to be built manually.

Model-driven app

Here, the app is built based on the data model in Dataverse. Lists, forms, and navigation come almost ready-made. It is suitable when there are many tables and relationships, and when the process is more important than the appearance—in other words, the same pattern used by Dynamics 365 itself.

The simple rule

If the app needs to do one thing quickly, especially on mobile, choose a canvas app. If it needs to manage structured data with relationships and roles, choose a model-driven app. If you're unsure, a model-driven app is the right choice more often than people think.