Frequency capping is the maximum number of communications that a contact can receive for each channel within the specified time period.
If the limit is reached, the contact will receive no more communication.
How does it work?
Once the frequency cap is enabled, you can define the communication limits of each channel.
The counts are applicable for both broadcast and journey.
For a broadcast campaign, the Frequency Capping is default applicable and you can skip it.
For a journey, the Frequency Capping needs to be enabled. By default it's disabled.
Once it's enabled, the user will not receive the communication and he will "removed from journey".
For detailed information, you can refer to Frequency Capping documentation