If you'd like to double-check that Plug in SEO Plus is installed correctly in your theme just go through these steps to avoid common pitfalls.
Check you don't have more than one Page Title
Plug in SEO Plus should be the only place where page titles are generated in your theme. You can check you have exactly one page title per page by using the Plug in SEO 'SEO problems' check.
Go to your Shopify admin > Apps > Plug in SEO. In Plug in SEO, press 'SEO problems'. The 'Page title' check should be a green tick. If not, check the 'How to fix' for more detail about how to fix. If you get stuck, email firstname.lastname@example.org.
Check you don't have more than one Meta Description
Exactly the same as 'Page Title' above, check you don't have more than one Meta Description in the 'SEO problems' 'Meta description' check in Plug in SEO.
Check your Structured Data is being generated
Plug in SEO Plus will generate Structured Data for all of your key page types. You can run the Google Structured Data Testing Tool to check this is happening. Pick one of each type of your pages: home, collection, page, blog, blog post, search and put their URL in the Structured Data testing tool.
If any issue is reported by the tool, make sure you've completed 'Editing and setting up Structured Data'.
Check that Plug in SEO Plus is in control
Sometimes other apps, your theme or a developer have changed things that means Plug in SEO Plus is no longer in control of your SEO data.
A simple way to check that Plug in SEO Plus is still in control is to set your homepage page title to something really obvious like 'TEST', check it has changed, and then switch it back to what it was.
So, look at 'Page title templates' here to find out how to set your homepage page title template. Once you press save, browse to your homepage in a desktop web browser and your TEST page title should be shown in the browser tab.
If it isn't, run through the Installing Plug in SEO Plus in your theme guide.
Need some help? Email email@example.com.