It depends. Do you check your email in a separate app or in Firefox? Also, what I'm about to say may vary depending on your device and Android version. Separate App: if you used the mail app recently, you can use the recent apps button to switch between Firefox and your mail app. Or tap the Home button and open your mail app, then use the recent apps button to switch back to Firefox. In Firefox: use the menu to open a new tab and check your mail in the new tab. Then tap the tab list button (usually a number on an icon that looks like a stack of paper) to switch back to your other tab. And please do not trust them with your bank account or credit card number because this could be a scam!