From your POS, you can see a list of Back in stock registrations the customer has signed up for and recent discounts sent to a customer and apply them to their active cart.
Add extensions to your POS Sales Channel
Navigate to your POS Sales Channel in the Shopify Admin
Select Settings
Select POS apps
Select Recent discount or Back in stock registrations
Click Add
Repeat for other extension
Note: Merchants must opt-in to these POS extensions to appear under customer profiles.
Finding the extensions in Shopify POS
Select Customers
Select any customer profile
Scroll to the bottom of their profile, and select Back in stock registrations or Recent discounts
Note: Things displayed in these extensions are unique per customer profile.