Thankfully it just takes a few moments.
Open the custom code embed below
Edit the text which reads "Here's an idea which I'd like to share #MadeInWebflow" after the var t = segment.
Press save and publish your site. Now when someone clicks on the Twitter icon, it will open up a modal to tweet the text that you added along with a link to your site page.
To customize what the tweet link looks like, just style it in the symbol found below