How to enable Single Store Mode in Magento 2

Single-Store Mode is disabled as setup default that leads to show a scope indicator whenever each configuration setting. Therefore, let enable single-store mode to simplify the display by turning off all Store View options and scope indicators if your Magento Community 2.0 installation has only a single store and view.

Learn how to enable single-store mode simply by following steps:

To set single store mode:

• On the Admin sidebar, click Stores. Then under Settings, select Configuration.
• In the panel on the left under General, select General.
• Scroll down to the bottom of the page, and expand the Single Store Mode section.
• Set Enable Single Store Mode to “Yes.”
• Click Save Config.
• When prompted to refresh the cache, do the following:
  • Click the Cache Management link in the system message at the top of the page
  • Mark the Page Cache checkbox.
  • With Actions set to “Refresh,” click Submit.

Ref: Magento 2 user guide