You can use Multi-Channel Fulfilment
by Amazon to continue fulfilling orders from your own website or other channels. When customers purchase products on your website or another third-party sales channel, Amazon receives your orders and picks, packs, and ships them directly to your customers. Note:
MCF is available with or without Fulfilment by Amazon (FBA). If you do use FBA to sell on Amazon, your existing inventory will serve both Amazon customers and customers from your other sales channels.