Summarize this article in one sentence.
This button has 9 squares in a 3x3 grid.   It can be found at the bottom of the Home screen. Tap the Settings app in your list of apps.  It generally has an icon that resembles a gear. Alternatively, you can swipe down from the top of the screen and tap the icon that resembles a gear.  It's in the upper-right corner. This may say "About device." You'll find this in the "System" or "Device manager" section. If your Settings menu has headings at the top, tap the More tab. Your phone number is listed at the top of the page next to "Phone Number."  If your number is showing as "Unknown" or is incorrect, you can use the Contacts app to fix it.  If you are using an older phone model and your phone number is not displayed on this page, continue with the following steps to find your number:  Tap Status in the "About Phone" menu if your phone number is not listed at the top of the "About Phone" app. Tap SIM status if you still do not see your phone number. Check the entry next to "My phone number."

Summary:
Tap the Apps button . Open the Settings menu . Scroll down and tap About phone. Check your phone number.