Coordinate System:
- Origin (0, 0) is at the bottom-left corner of the page
- Units are in points (1 point = 1/72 inch)
- Standard letter size: 612 x 792 points (8.5" x 11")
- X increases to the right, Y increases upward
Field Name: Must match the field identifier used in PDF field mapping (e.g., EmployeeLastName, SIN, Box14, PayerName)