mPDF not only allows the creation of PDF documents from HTML content but can also convert HTML form objects into interactive PDF objects allowing the resulting PDF forms to to completed on desktop and mobile.
The following example takes a simple HTML form and by using the mPDF parameter:
$mpdf->useActiveForms = true;
enables the fillable feature of PDF forms.
All you then need is the Adobe Reader or PDF Studio or any of the other PDF viewers that support interactive PDF form objects to complete the form.
View the code of the sample HTML form page.