In your website dashboard, check to see if the All-In-One SEO plugin is present in the left sidebar. This plugin is necessary because you will place a code within its program.

Note: If you don't see the plugin in the left sidebar, you'll need to activate the All-In-One SEO plugin. Click on: Plugins, Click on: New Plugins and All-In-One SEO should be first in the list of available plugins. If not, type it in the search bar. Click on: Activate. All-In-One SEO should appear in the left sidebar.

Next:
Open a new tab in your browser and type in: Google Search Console.
Click on: Google Search Console.

The next web page should look like this:

Type or copy and paste your website URL in the location I have highlighted in red.
Click: Add A Property

Next Page: Choose a method