Is this the simplest way?
Right in a view code something like this:
def resume_edit(request, r_id):
.....
r = Resume.get.object(pk=r_id)
resume = ResumeModelForm(instance=r)
.....
resume.fields['email'].widget.attrs['readonly'] = True
.....
return render(request, 'resumes/resume.html', context)
It works fine!