Recent tax law changes in many US states, as well as Australia and New Zealand, require that Biblio calculate, collect and remit sales tax. You do not need to request additional funds to cover sales tax when orders are shipping to one of the affected US states, Australia or New Zealand. Biblio will be doing that for you. Here's a link to a chart of affected places:
And here's a link for information specific to Australian and New Zealand GST.
If your bookselling business IS NOT located in one of those places, there's nothing you need to do. Biblio will calculate and collect sales tax as part of the checkout process and then remit those payments to the appropriate Department of Revenue. You'll see the sales tax figures in the order details, but you won't be responsible for calculating or remitting those taxes.
If your bookselling business IS located in one of those places, Biblio will automatically calculate and collect sales tax during the checkout process for orders where sales tax applies. Biblio will then report and remit this sales tax on your behalf and you'll be able to deduct that amount from the sales tax you owe for combined sales.
This will apply to all orders shipping to the affected US states, New Zealand and Australia, regardless of where the bookseller's business is located. Sales tax added to an order will not affect commission or payment processing fees on that order, nor will it affect the amount paid out to sellers for these orders.
You should consult your professional tax advisor if you have any questions about your particular tax liability.