Add an underline style to headers and text (not for hyperlinks). This plugin uses css editor and works with all template families.

From your Squarespace account, go to the Custom CSS Editor. Copy and paste the code below into the Custom CSS Editor box.

Change the h1 text property to the one you’d like to target. This can be either h1, h2, or h3.

Adjust both of the text-decoration and text-decoration-thickness values to your liking.