To add a Checkbox field in the Design section, click Add Form Field then select Checkbox.
The field will be added to your form and a slider menu will open on the left where you can edit the field’s label, make the checkbox marked by default, and make the field required.
In the left sidebar menu, you can click the six dots to the left of the field and drag up or down to reposition the field on the form, or use the “trash can” icon to delete the field.