Need to give my own answer, as @Christian gave almost correct and working URL of an example and I found this on Github for active forms but when I tried my html form with it, then it gives me error something like,
Fatal error: Call to undefined method mPDF::Error() .... mpdf\classes\mpdfform.php on line 839
After some searching I found that there is missing name
attribute in the form's text field and when I added the attribute it worked well.
<input type="text" id="name" value="name" name="field_name" />
The problem not ends with this, when I submit the form then there is nothing shown in browser's console. Then I used php://input at server side and it has shown me some response, which is in FDF(forms data format) and needs to be parse to get the actual data. I din't give a try to parse it but found some useful URLS which I am sharing here,