In one sentence, describe what the following article is about:

Tap the app icon of the browser that you want to open. You can close tabs on Chrome and Firefox for both iPhone and Android, as well as Safari for iPhone. Doing so will bring up a list of your currently open tabs. This icon's appearance and location varies depending on the browser:   Chrome and Firefox - Tap the numbered box in the top-right corner of the screen.  Safari - Tap the two overlapping boxes in the bottom-right side of the screen. You can scroll up or down through the currently open tabs until you find the one you want to close. It's in the top-left corner of the tab that you want to close. This will immediately close the tab. You can also close tabs by swiping them to the left.

Summary:
Open a browser. Tap the "Tabs" icon. Look for the tab you want to close. Tap X.