• Paper (paper_w, paper_h)
PDF page width and height in mm (A4 = 210×297). Must match the actual size of the uploaded PDF.

• Offset X / Y (offset_x, offset_y)
Shifts the whole page when printing:

• offset_x > 0 → right
• offset_x < 0 → left
• offset_y > 0 → down
• offset_y < 0 → up

Example: offset_x = -2 shifts the whole page 2 mm to the left.

• Field coordinates (x, y)
Every field has x/y in mm, measured from the top-left corner of the PDF. Clicking the PDF preview fills in the coordinates automatically.

• Editing an existing field
Click a field in the "Fields on this page" list — its values load into the form and the button changes to "Save changes". Click the PDF to change its position too, then confirm. The 🗑 button deletes a field.

• Fine-tuning a single field
For precise alignment:

• x + 0.1 → 0.1 mm right
• x - 0.1 → 0.1 mm left
• y + 0.1 → 0.1 mm down
• y - 0.1 → 0.1 mm up

Recommended: steps of 0.1–0.3 mm for fine corrections.
• Regular field (type: "text")
Standard text – name, surname, date, amount…

• Boxed fields (type: "boxed")
For forms with per-character boxes (invoices, reference numbers, ID numbers…):

• boxes – number of boxes
• box_w – width of a single box (mm)
• box_h – height of a single box (mm)
• w = boxes × box_w – total field width

The designer works in millimeters – ideal for precise printing.