To begin with, let's visit google.com/webmasters to create our free account (Sign in if you already have one)
Once you are inside the dashboard, you will see the option to add a property. Copy your Shopify store's URL from the address bar of the browser and paste it in the space as shown above. Then click ADD A PROPERTY button.
Verify your site
Once you have added your website, it will ask you to verify your ownership. There are several methods to do that. The easiest way is by using any of the Alternate methods
To verify your Shopify store via the Google Analytics option, you must have a Google Analytics account set up for your Shopify store with the same email id you have used for the Webmaster Tools account. Also, the Google Analytics tracking code should already be there on your Shopify store. If you don't have the Google Analytics setup for your Shopify store, do it first as you will need it anyway. If you have set up your Google Analytics account with different email id then just give the Edit permission from your Analytics account to the email id used for the Webmaster Tools. Once you have the Analytics account set up, select that option and click Verify.
To verify with the HTML Tag option, click on the radio button,
Copy the HTML code that will be generated, go to your Themes in Shopify under the Online Store menu option, click in the Actions button in your current theme and then on the Edit code option in the drop-down menu
Look out for “theme.liquid” in your theme files. Open this file, and right under the <head> tag, paste the code Google generated for you and click on the save button in the top right corner.
After you're done doing that, go back to Google webmaster and click the Verify button at the bottom of the page. If you got this all done right the page should load and you should see this.
Click continue and you can begin your journey with Google webmaster. You will be sent to your dashboard. Feel free to explore and find out how the options work.