specifying the color of an item in the bill...

[llomartz]

If the seller says:

"Please mark the color (of the item) in your Paypal bill , otherwise, I'll send Either Colors to you"

where and how can I specify that information on the bill?

[skier]

One option is to use the Note to seller which you will see during the Checkout Process.   If the seller has this feature disabled, you will have to contact him or her separately.

Regards,

skier