When a text is filled in description then it should be defaulted automatically. The feature is available in Ax 2009 and Ax 2012 versions.

1. General Journal
2. Customer Payments
3. Vendor Payments

General Journal or Customer Payments or any journal which contains the field Description.

In the first line “Test the description” is entered, and when the second line has some description, if we press “T”, then the rest of the line should get populated automatically.