How to enable the Header Top Bar?

• From your WordPress Dashboard, go to Appearance > Customize > Header > Header Top Bar section.
• Toggle on the Enable Header Top Bar option to reveal the header top bar options.
• Click on Publish.

It is shown in the image below:

You might not see any changes just after enabling the Header Top Bar. In that case, you will have to add the content as instructed here: How to add content on Header Top Bar?