To view a prospect's Marketing Cloud Account Engagement landing page submission activity on the syncing contact in Salesforce, an Administrator can use the following features:
The Marketing Cloud Account Engagement Activities Visualforce page, which shows a detailed history of the prospect's interactions with Marketing Cloud Account Engagement assets, including landing pages, forms, emails, and custom redirects.
The Salesforce Activities section, which shows the tasks and events that are logged for the contact, including Marketing Cloud Account Engagement landing page submissions. Reference: [Marketing Cloud Account Engagement Activities Visualforce Page], [Salesforce Activities]