Often, it's helpful to reference specific object fields to make an automation more useful.
For example, when sending an email notification regarding a deal at risk, it is helpful to include the Account.Name, Opportunity.Amount, and even a link to the related object.
Macros allow you to pass values into Rule and Action fields to make this possible.
What objects/fields are supported?
Any related object/field that is captured by the Tracker can be accessed within a macro.
This includes related Accounts, Opportunities, Contacts, Leads, Tasks, Transcriptions and Users.
What Action types are supported?
Macros work with all Action types, including those that take JSON values.
For example, if you wanted to push information to a third party system, you could still use macros in the following way:
{"OpportunityName": "{{Opportunity.Name}}"}