You can create an email listener rule where you can mention the folder from which the emails will be taken for the processing. In the below screen-shot, as we we have configured the Inbox as our folder, the email listener picks the emails from this folder.
@LuisB647 For Pega Robotics, the first thing you'd do is add an Outlook Connector (I suggest placing this in a Global Container). You'd then use the FindEmail method to locate your specific email. This method takes a folder as a parameter, so you can give it a path relative to your Inbox. Another way to locate an email is to iterate though a folder by using the RetrieveEmail method. This returns a collection of emails from a folder. You can pass this to a ListLoop to iterate each one. From the ListLoop, you'd extract a proxy to view the properties of each individual email. One of these properties is "Body" from which you can extract the contents of the body to use however you wish.