The answer varies depending on your policy and in the [Channel Managers Dashboard > Booking.com] menu on your Stays.net you can follow the steps bellow:

Situation	Answer	Compatible Configuration
I linked my Stays fees with Booking	If you have linked the fees on the [Settings > Fees & Taxes], in this case, we will follow the same configuration you used when creating the fee on Stays.
I did not link the fees	In this case, you will need to choose the invoice you want in this configuration below in your Stays.net panel, on the [Finance > Relation with Fees & Taxes] menu.