Can I exchange my newly purchased iPhone 16 Plus for a Pro Max?

You have 14 days to return a purchase made from Apple, so you would need to get a refund on yours first and then purchase the Pro Max. There is no upgrade option where you can just pay the difference on an exchange.

Click here to read about Apple Store Returns & Refunds--> Returns & Refunds - Shopping Help - Apple - For the USA "You have 14 calendar days to return an item from the date you received it." The return terms may be different in some countries (the link I provide should open to a page for the country to which your account is set).

- "You can always return the item to any U.S. Apple Store. An Apple Specialist will assist you with your return. Your refund will be processed at that time"

If you got it from an Apple Store, you have 14 days to return it for a full refund.

If you bought from Apple, you have 14 days to return the phnone for a refund.....no questions asked. You can spend or save the refund.....up to you.