API Keys - help please :)

Hi everyone, I'm in need of help regarding API keys...I can't seem to find an answer anywhere.

I'm currently building a website for my client. He is a mortgage broker who wants a button on his home page entitled "I want to refinance". He wants this button to open a form on his squarespace website that captures client details for a finance application, so that when you hit submit, the form is submitted directly into his CRM.

Is this a simple matter of embedding a code - if not, what is required to enable this function?

Any help would be extremely appreciated!!

Thanks for your reply Creedon. It turns out their was confusion with what the client was describing. It's not an API key - thankfully I have sorted it now. Thanks for your help in any case!