Need Help!!

Hi i need help

Im creating website for online influences to sell there merchandise and i would like for them to be notified when one of there items sell but I don't know how to do that.

What I need is a system / interface that allows partners to view when one of their items have sold to begin with I just want something simple that notifies them when an item sells but I want something more interactive in the future.

Would love to hear if anyone has done this or how i could do it myself thanks.