There are 5 Page Title Bar style for you to select from.
Step 1: Navigate to Appearance >> Customize >> Page Title Bar
Step 2: Choose General
Now you can choose to enable it or not
You also can customize default Page Title Bar by crolling down and customize the sections below
For example: Search Heading
This is how the text you enter in this section will display on the search result page.
Step 3: Click on Publish button to finish.