Add form (in lightbox) to site header in lieu of button

Hello! I'm wondering if it is possible to add a form to a site header where the button usually is. I would love if they could hit a button and, instead of opening up an email or linking to another page, a lightbox form modal would appear.

You need to use JavaScript or try this guide (contain affiliate link)

hi @okaykeating, 

I use the Lightbox Anything (aff) plugin for this exact thing in my footer.

You can see another example of how I use it in my blog post 3 Best Squarespace Plug-ins