Let us illustrate this with an example:
1. In a PDF document you would like to automatically fill a checkbox, in this example the gender: male or female.
![](https://cdn.statically.io/img/mailmergic.com/wp-content/uploads/2020/11/Automatically-fill-the-checkbox-of-a-pdf-form-1-3.png?quality=80&f=auto)
2. Create two columns in your Excel spreadsheet. Fill one column with an “x” if the person is male and the other column with an “x” if the person is female.
![](https://cdn.statically.io/img/mailmergic.com/wp-content/uploads/2020/11/Automatically-fill-the-checkbox-of-a-pdf-form-2-1024x444.png?quality=80&f=auto)
3. Drag the placeholders onto the checkboxes in our editor. Make sure that you align the first letter of the placeholder text exactly with the box.
![](https://cdn.statically.io/img/mailmergic.com/wp-content/uploads/2020/11/Automatically-fill-the-checkbox-of-a-pdf-form-3-1.png?quality=80&f=auto)
4. When you start the Mail Merge, the x from the gender columns will be printed accordingly into the checkboxes.
![](https://cdn.statically.io/img/mailmergic.com/wp-content/uploads/2020/11/Automatically-fill-the-checkbox-of-a-pdf-form-4.png?quality=80&f=auto)