And for changing the page title, here are the steps
1. Edit the “About Us” page.
2. At the very top-right in the admin panel, just beside the help, you can see “Screen Options”. Click on it.
3. In the “Show on screen” option, please check the “Custom Fields” checkbox. Now you should see that you can edit the custom field section at the bottom.
4. Just remove the value for the custom field “mo_description” or you can insert your own description, if you like.
Hope this helps.