Transaction data keeps on changing and deals with day to day activities carried out in business or different departments. For example, the transactions done by or with Customers, Vendors, and Materials etc. generate Transaction Data. So data related to Sales, Purchases, Deliveries, Invoices etc. represent transaction data.
Master data is data that does not change often and is always needed in the same way by business and various departments in the organization. Master Data is key business information that supports the transactions. For example, one time activities like creating Company Codes, Materials, Vendors, Customers etc.
Reference data is data which holds additional information to make a data set complete. Reference Data is frequently considered as a subset of master data. It is data that is referenced and shared by a number of systems. Most of the reference data refers to concepts that impact business processes. For example, the order status which can be Created, Approved, Rejected, Pending etc.