Hello,
In order to create a custom label, navigate to Products > Attributes > create attribute > then add terms to the created attribute.
Edit the attribute itself – and enable the Show attribute label on products option:
https://postimg.cc/wyfLtqD3
Edit the product for which you want to show the custom label and assign that custom label attribute to the product.
For more details, follow this guide: https://xtemos.com/docs-topic/product-labels/
Best Regards