Amazon FBM, or Fulfilled by Merchant, is a fulfillment option offered by Amazon.com that allows sellers to fulfill orders placed on the Amazon marketplace using their own inventory and shipping methods.

If you are a seller using FBM, you are responsible for storing and shipping your own products to Amazon customers. When a customer places an order for one of your products, Amazon will notify you and provide the shipping address. You will then package and ship the product to the customer.

Using FBM can be a good option for sellers who want to have more control over their fulfillment process and who do not want to pay the additional fees associated with Amazon's fulfillment service (Fulfilled by Amazon, or FBA). However, it requires more effort and coordination on the part of the seller, as you are responsible for handling all aspects of fulfillment.