How to retrieve the legal status of American patents?

The legal status of U.S. patents needs to be inquired on the website of the U.S. Patent and Trademark Office (http://www.uspto.gov/). The general steps are as follows: through the website of the US Patent and Trademark Office, enter the public query database (public pair); Enter the verification code for verification; Enter the patent number for inquiry; Obtain the basic information of the inquired patent; That is, you can see the status of the inquired patent, or you can query the patent examination process information through the "Image File Wrapper" tab and the patent fee information through the "Expense" tab.