From the Controls Gallery on the Home tab or the Controls task pane, click the Person/Group Picker to insert it into the view.
The Person/Group Picker needs to connect to a SharePoint site to be able to function. Specify the SharePoint site as follows, unless you have already published the form to a SharePoint site, in which case that site will be used.
- Right-click the control in the view and select Person/Group Picker Properties from the context menu
- In the Person/Group Picker Properties dialog, select the SharePoint Server tab
- Type the URL of the SharePoint site you want to query
- Click OK to close the dialog
Specifying data validation (optional)
In InfoPath 2010 it is now possible to mark the field the people picker is bound to as Cannot be blank. This means that users will not be able to submit a form without having entered at least one valid person or group in the control. You can mark a field as required by doing the following:
- Select the control in the view
- In the Properties tab in the Modify chunk, click the Cannot be blank checkbox
Testing the control
Preview the form in InfoPath Designer or publish the form to a SharePoint site and view the form, enter a name or logon alias, click the “Check Names” button and resolve the name! Alternatively, you can click the “Address book” button to perform a search if you do not know the complete name of the user.
More Information here: