PDF Form edit and email

I have a Gift Aid Declaration form in PDF format. I want to put it on a website and ask users to fill in their details then click on a 'submit' button and the completed form will then be emailed to our Gift Aid administrator.

Can anyone recommend any free software (windows) that will allow me to set this up?

I say free because this is a one-off job and the charity cannot afford the money for something that will only be used once.

Thanking you in advance.