How to use automatic Chatter posts
Chatter is an inbuilt social media platform designed for Salesforce.
Chatter updates can only currently be generated for transactions that are created/updated by an internal user and not from the online payment checkout form. This is due to a restriction in place by salesforce.com. If you wish to track these updates, then it is suggested to enable chatter feed tracking on the Payment Transaction Object field “Chatter Posts”.
Before Chatter posts can be used, you need to enable chatter posts for the Payment Txn Object
Navigate to Setup > Feature Setting > Chatter > Feed Tracking (Lightning)
The Merchant Facility tab can be found within the Payments2Us menu (Top right picklist in Salesforce - Select Payments2Us), or it can be found under the "More" at the end of the tabs. (In Salesforce Classic - It can be under the "+" at the end of the tabs)
Once you have clicked on the Merchant Facility Tab, select the appropriate List view (Example - "All Merchant Facilities") and click into Merchant Facility you wish to update.