Simple definition
An Intune assignment filter refines application or policy targeting according to managed device properties.
Purpose and use
An Intune assignment filter refines targeting for a supported app or policy using device or managed-app properties.
How does it work?
An expression is evaluated within an assignment to include or exclude objects matching supported criteria.
Example and verification
Before wider rollout, inspect previews and reports on representative devices, especially when versions or properties change.
Points to watch
Not every policy type supports the same filters. An assignment filter does not replace administrator roles or Conditional Access rules.
In short
Filters control part of effective targeting alongside groups and compatibility conditions.