Click the "Mobile Scan Object Permission" object.

Scroll down to the "Values" section and click "New".

Enter 'Event_Lead' and 'Event_Contact' in the text field, each on a separate line.

After inputting the values, click "Save".

Fields now appear in the 'Available' column of the Lead(Event) and Contact(Event) tabs.

The Scan app will display all available fields in the event page layout until fields are added to the 'Selected' column for the Lead(Event) and Contact(Event) page layouts.

Add Field Options to the Lead(Event) and Contact(Event) Page Layouts