It might be better if you create a second copy of the form (as suggested by @Redpelon) as a manual printable and fillable by hand version of the form - but depends on if your electronic form uses drop-down fields, other interactive elements and conditional logic etc. (hiding/showing fields and so on) which wouldn't obviously work on a printed form, so the method of collecting that infomration would have to be presented differently in the printed version of the form.
You could put a print button on the electronic form, using such code as:
<p>Click the button to print the current page.</p>
<button onclick="myFunction()">Print this page</button>
<script>
function myFunction() {
window.print();
}
</script>
(Attrib: http://www.w3schools.com/jsref/met_win_print.asp)
The code would be placed in a field such as a section break. This might not work in all browsers, so the user would need to use the "print" button in their browser tool-bar, or the Print option on File menu.
For concerns about your clients not wanting to submit their email address online, that field would not necessarily need to be a "required" field and could be left blank.