Unfortunately, Substack does not offer a pop-up form that you can embed in your website. If you're using Squarespace, here are 3 suggested workarounds for using the Squarespace pop-up tool to encourage Substack subscribers.
This video applies to Squarespace version 7.1
00:00 - Option 1: Use your pop-up to send visitors to Substack
05:00 - Option 2: Use your pop-up to store names in a Squarespace list, then transfer them to Substack
11:53 - Option 3: Use your pop-up to store names in a Google sheet, then transfer them to Substack
For each option, when you've finished setting it up, make sure you toggle the Display Pop-Up slider at the top so that it's green. And be sure to test your pop-up!
You can find my tips for testing your pop-up (including how to browse in private or incognito mode), as well as a link to the Substack import instructions, in the accompanying blog post instructions here:
https://www.paulinewiles.com/articles...
Find out more about hiring me for Squarespace website design, specializing in websites for authors and solopreneurs with books, at https://www.paulinewiles.com/