When using the tag Salary_SalaryAmount it will not automatically add a comma to salary amount.
To get the comma to show, you will need to:
Insert the merge tag Salary_SalaryAmount, then right-click on it.
Click Toggle Field Codes and type \#,0.00 at the end of the text, before the closing curly brace.
📌Note: It should show like this { MERGEFIELD Salary-SalaryAmount \#,0.00 }.
Click Toggle Field Codes.