We recommend registering your business as a legal U.S. entity before applying to be a U.S. seller on Amazon. It will be smoother for a U.S. company to register for Amazon. And Amazon, as a U.S. company, provides more help of U.S. based businesses, and will take care of them in terms of store closures, promotions, etc.

To open an Amazon seller account with a U.S. company, you must follow the below procedures:

1. Register a U.S. Company
   
   If you’re not a citizen or a resident of the United States, you can create a legal business entity: an LLC (limited liability company) or a C-Corp (or corporation).
   
   
2. Apply for EIN
   
   For U.S. taxpayers, a Tax Identification Number is required by the IRS for the administration of tax laws. You need to provide either an Employer Identification Number (EIN) or a Social Security Number (SSN) to complete the Amazon U.S. Tax Identity Information Interview.
   
   
3. Credit Card and Bank Account Setup
   
   When you register in Amazon as a seller, it is necessary to enter an internationally chargeable credit card with a valid billing address located in an eligible country. Upon completion of registration, your credit card will be charged the monthly fee to validate the credit card.
   
   Note: The card should be chargeable in the currency of the Amazon store(s) for which the card is being provided.
   
   
4. Setup Amazon Seller Account
   
   Go to https://sellercentral.amazon.com/ to create your Amazon seller account. Amazon will require some additional proofs for identity verification. The review process can take up to two business days. Amazon will email you the result.
   
   

You will need the following documents to register a U.S. company and Amazon seller account.

1. Documents Required to Register a Company in U.S.
   
   For the purpose of registering a corporation in Delaware, the following materials should be prepared and provided:
   
   

   (1)	Names of the proposed company. Please provide 2 to 3 preferred names in priority order;
   (2)	Passport copy and residential address proof (utility bill, phone bill, or bank statement, etc for the most recent 3 months) in respect of each shareholder/member, director, officer (and secretary, if requested) of the Company. If the shareholder/member is a legal entity, please provide the entity’s registration document and registered address for our record;
   (3)	The maximum number of shares authorized by its board of directors and the par value or registered capital and each member’s share of profits and losses (if more than one member);
   (4)	The detailed description of the company’s main business activities, such as the services intend to offer or products intend to sell, and the location of potential customers/suppliers;
   (5)	Date of commencement of business;
   (6)	Numbers of employees, if any;
   (7)	Duly completed “due diligence questionnaire” provided by Kaizen.

   
   The identification and address proof, mentioned in (2), should be certified or notarized by Kaizen, local notary at the place of the shareholder and manager, lawyer, CPA, or bank manager.
   
   
2. Amazon Seller Account Setup
   
   

   (1)	A valid email to register Amazon seller account.
   (2)	U.S. company registration document, including business name, registered state, company registration number, and registered business address. Amazon may verify the registered business address by sending a postcard containing a verification code.
   (3)	Mobile or telephone number which can receive SMS or call for verification.
   (4)	Full name of the primary contact person.
   (5)	Passport/National ID Copy, the residential address and the mobile number of the legal representative/beneficial owner of the business.
   (6)	A valid bank account information, including the financial institution name, name registered with bank account, bank account country, 9-digit routing number and the bank account number.
   (7)	A valid credit card number which will be used to pay the Amazon monthly fee.
   (8)	Amazon store name, Universal Product Codes (if applicable), diversity certifications (e.g. Minority, Women, Veteran, or LGBT-owned business, if applicable), government-registered trademark for the branded products (if applicable).
   (9)	Employer Identification Number (EIN) to complete the Amazon U.S. tax identity information interview.

   
   Note:
   

   (1)	The bank account should be in the name of the primary contact or business name provided to Amazon.
   (2)	To verify the bank account you will be required to upload a bank statement or credit card statement to Amazon.
   (3)	Additional documents may be required by Amazon for verification purpose.

[Reference]:
https://sellercentral.amazon.com/gp/help/GUQLF3C3HXXXERLC
https://sellercentral.amazon.com/gp/help/external/200663290?language=en-US&ref=mpbc_200663310_cont_200663290
https://sellercentral.amazon.com/gp/help/external/VYFQEJQAF2TSYEH

See also:
U.S. Company Incorporation
US EIN Application Procedures and Fees