1. Query through browser history: Open a browser, find the records of websites or login pages related to email accounts, and click to view details.
2. Inquire through email client or application: Open relevant application to view settings or account information. E-mail addresses are usually displayed here.
3. Check the form filling record: enter the login page of the e-mail service provider, check the browser's form filling record or automatic form filling option, and find relevant information.