June here from Shopify. I'd love to hear more about exactly what you're hoping to achieve here.
Is the goal to add a "Sale" badge to your homepage Featured product section, similarly to how you can on your product thumbnails? You'll notice in the image below I have edited the sale badge which originally read "Save $5" to say "SALE" via the language editor - let me know if I can help you do the same!
In regards to your homepage's Featured product section, currently the expected behaviour is to display the sale price itself, for example:
Definitely let me know if this is in fact what you are hoping to edit and we can take a look at your options. Of course, if you're trying to do something else entirely, don't hesitate to clarify what that is and we can chat more about it.
Thanks again for getting in touch!