You no need to add any third party app for this function, we can do it with some tweaks in theme file and you can manage it from theme settings whenever you want easily. Let me know if you want to do it and send me more inform to my mail. definitely I will help you on that.
I'm new to the Shopify community, and I came across your question on adding a custom badge in your product catalogs. Hope your issue was resolved. FYI, we have developed an app (Modemagic) that will allow you to add product stickers/badges on your catalog within seconds. Check out this app on Shopify here. We have an extensive collection of stickers/badges suiting to any need. No complex edits, no back & forth with designers. Update your store within a few minutes!
Hope this helps :) Do let me know if you need any help.
PS: CoVid offer for all stores at https://community.shopify.com/c/COVID-19-Partner-Offers/Free-Credits-for-In-Store-Conversion-Sticke...