When viewing by Mobile View (browser of your phone devices), there is a "Sign in" button to click to open a popup, it allows you to enter credential to log in into the site.

You will find a phrase as "Sign in to sitename", and you do not know how to translate it to your language.

Let's guide you below

1. Go to AdminCP >> Globalization >> Phrases >> Search For Text = Sign in to sitename >> "Search" button

2. Rebuild Core Theme and Clear Cache

May 17, 2019