Custom code to add anchor link in a fixed position as user scrolls down page

Hi!

A client wants me to replicate this phone icon that sits on the bottom corner of the page in a fixed position as scrolling through the website. As it appears on this website https://www.coreclapton.org/

I know Squarespace doesn't have this feature available.

Can anyone share the custom code to add this on Squarespace? And explain how to add it on the page?

It's sort of an anchor link but sits on a layer above the sections.

Thank you ver much!

Click Call icon >> Scroll to footer or open call app or open new page?

Thanks for the reply! Client wants Click Call icon >> Scroll to footer

Is it possible at all?

I might try combining this with the id that the footer already has of #footer-sections and change the display of Will's button to be your call button.

https://www.will-myers.com/articles/building-a-back-to-top-button-in-squarespace