What is a reference field?
A reference field is any field in Salesforce that "'refers to" another object that contains its own fields - whether that be an Account, Lead, Contact, etc. They are most easily identified by containing a link that allows you travel to that Object in Salesforce if clicked.
In this case, the Account is referenced on the Opportunity:
Why would I use this?
Displaying fields from other Objects comes in handy for a variety of reasons. Let's say you want to show Account details when an Opportunity stage changes, or the Company/Phone Number/Email of a Lead on an alert that is triggered when a new meeting is set. Being able to tap into fields on referenced objects allows you to do this.
How can I set up my alert to show fields from other Objects?
It's easy. When setting up a workflow on app.troops.ai, the new field selector lets you add in fields from references Objects. The referenced objects are displayed on the left-hand sidebar.
Here, I've set up an Opportunity alert to fire whenever a Stage moves to Intro, and I've included some information from the Account.
What's up with the names of people from my team?
Users in Salesforce on objects (e.g., an Opportunity owner) are also referenced objects - you have not only the person's name but email, phone number, etc. Just make sure to select what you want to show.
What if my referenced Object contains a field with another referenced Object?
You get Inception-ed and can never escape. Just kidding - in that case, if that field is selected to show on the alert, whatever is being displayed on the field in Salesforce will be displayed on the Troops alert as well.