TOPIC:

I'd like to know if it's possible to menage checkbox group. I have a PDF with, for example, 2 checkbox with same name but different export value.

For example a YES/NO check with name "QuestionCheck1" and different export value, YES checked 1, YES unchecked 0, NO checked 3, No unchecked 2

Sorry, but can you please make the request more clear? Do you mean there are two different forms in one PDF document each with one checkbox, and you would like to merge the two forms into one? If I check both the checkboxes what are you expecting for the export value? "1 and 3" or "4"? Thank you.

No. You have single page pdf with a series of questions and answer.
For example: 1 Question: Are you a football player? YES NO

The YES/NO are two checkbox with same name (chkquestion1) but with different export value, so if I check if chkquestion is true o false I can't do that because both have same name.
Probably you say: why? Why you can't name it different?
Because I don't make the PDF, is a customer request mandatory.
At my company this example names MUTUAL CHECKBOX.

OK, so your issue is actually two checkboxes with the same name. Sorry, you cannot modify the export value to 2 and 3 since it violates Adobe PDF standard (value 2 and 3 are used for radio button). But you can use Annotation.GetIndexInPage() method to get a unique index reference for each annotation in the same page. Hope this can help you.