Need help cloaking link to an external survey/form

Hoping someone can help me out here.

I was given a link to a form that is hosted externally and it needs to be masked. How can I do this without using a plugin? The link needs to be cloaked so that it always appears to come from my domain, not just redirected to the domain which is actually hosting the form.

If I could be given a good set of instructions, I’d have no problem implementing this, but I haven’t seen consistent methods in tutorials to achieve what I want.