It is one of the recent feature available in Dynamics 365, it is more effective way of tracking the Email conversation,Activities

 

Here are the steps to enable:

Go to to sales Hub 

Select Sales Insight Settings

Select tick box and  click get started

Select consent tick box and click accept button

click on continue

It will take few minutes to Install

 After completion below screen will appear

Now go to Contact Form and make this section visible by default