In Shopify Admin navigate to Online Store > Themes and click "Customize". Learn more about customizing themes.
Within the theme editor, navigate to the customer profile page.
In the apps' sidebar, search for "Barcodify - Customer Selector" and add the "Customer barcodes" extension.
Enter the store's .myshopify.com domain name as displayed in the admin settings below the store's name.
Optionally, add custom text to title and subtitle fields.
If you wish to change the block's placement, move it using the arrow buttons below.
Save the changes (top right).
The app's customer account UI extension currently doesn't support text translations. If you require this or any other customisations, please email me hello@galmis.com and I'll be happy to help.