Tap the check box beside Auto Sign-in to remove the check mark.Tap on the three dots icon on the upper right side of the screen.However, you can manually turn it off by following these steps.
Disable Chrome Auto Sign-in for Androidīy default, the Google Chrome App for Android devices enables the auto sign-in feature. With Chrome auto sign-in disabled, you can sign into Google sites like Gmail or Docs and, just like in older versions of Chrome, remained signed out of the browser. To test that this worked, close and then re-open Chrome.