Hello,

1. In order to create a custom label, navigate to Products > Attributes > create attribute > then add terms to created attribute – https://prnt.sc/tqzG6kgJCwEQ, https://prnt.sc/yq_ZcONu22_n

Edit the attribute itself – https://prnt.sc/ExOeF6K7T_U3 and enable the “Show attribute label on products” option – https://prnt.sc/7vckb4xRhteN

2. Edit the product for which you want to show the custom label and assign that custom label attribute to the product – https://prnt.sc/QGfKsahh3O9a

As a result the custom label will be shown.
https://prnt.sc/Oepo-lw1A_l7

Best Regards