How to add Store Name or website url to paypal express checkout

[sloan]

Currently using zencart 1.5.7C and paypal express checkout

I have several websites (all use paypal express checkout) and use a single paypal account.

I can't tell the order from which website when I got the paypal payment notification email.

The content in the payment notification email I received from paypal mainly includes:
item name+attribute+item number
I want to add the website name (STORE_NAME), for example, change the item number to STORE_NAME+item number.

So how to achieve this purpose?

Thank you!

[DrByte]

The transaction data sent to PayPal includes the store name in the "Invoice Number" field (not the "order number", not the "transaction number").
It's "customer ID" + "current time" + "store name":

https://github.com/zencart/zencart/b....php#L395-L396

[sloan]

Thank you.
I see now.
Because the two domains of my sites are similar, and the store name(domain) has been cut and replaced, so I did not recognize it.