The two activities that trigger a prospect record to sync from Marketing Cloud Account Engagement to the CRM are landing page submission and form submission. A prospect record is a record that contains the information and activities of a potential customer in Marketing Cloud Account Engagement. A sync is a process that updates the data between Marketing Cloud Account Engagement and your CRM system, such as Salesforce or Microsoft Dynamics. A sync can be initiated from Marketing Cloud Account Engagement to the CRM, or from the CRM to Marketing Cloud Account Engagement, depending on the activity or the data change. A landing page submission is an activity that occurs when a prospect fills out a form on a landing page, which is a web page that you create and host in Marketing Cloud Account Engagement to showcase your products or services, offer content, or register for events. A form submission is an activity that occurs when a prospect fills out a form, which is a web element that allows you to collect information from your prospects, such as their name, email, or company. Both landing page submission and form submission trigger a prospect record to sync from Marketing Cloud Account Engagement to the CRM, because they create or update the prospect data in Marketing Cloud Account Engagement, and Marketing Cloud Account Engagement pushes the data to the CRM