Apps creator apps send Platform Name and Event Label with each logged Event to your GA4 property. However to access those in your GA4 property you need to create two Custom Definition in your GA4 account.
Follow the below steps to add these Custom Definitions:
Step 1: Login to your linked Google Analytics Account.
Step 2: Click on the cog wheel icon in the bottom left corner of the home page.
Step 3: Click on Custom Definitions, as shown in the screenshot below.
Step 4: Click on Create Custom Dimension, to create a new Dimension.
Step 5: Enter the Name as "EventLabel", the Scope as "Event" and the Event Parameter as "Label", and click Save.
Step 6: Now create another Custom Dimension with the following values and save:
Event Name: PlatformType
Event Parameter: Platform_Type
You have successfully created the custom definitions for Platform Type and Event Labels. This can take upto 24hrs to take effect in your GA4. After 24hrs, you will be able to see these custom dimensions when exploring individual Event types under Events.
Data in these Custom Definitions will start populating from the date they become active in your GA4 property, any historical data will not be shown under these custom definitions. Therefore, it is recommended that you create these custom definitions while initial setup of your GA4 property.