Your markup
Which type to use
Pick the type that describes the page you are on, not the business behind it. A service page is a Service, an article is a BlogPosting, and a contact or home page for a business with a real address is a LocalBusiness. Marking every page as LocalBusiness is the most common mistake and it gives a search engine contradictory signals about what each page is for.
Breadcrumb markup is worth adding almost everywhere, because it changes what appears in place of the raw URL in the result. FAQ markup only belongs on a page whose questions and answers a visitor can actually read on the page itself.
Required properties are not optional
Every type has properties without which the markup is ignored. An Article without an author, a Product without a price and currency, a LocalBusiness without a name and URL: these validate as errors, not warnings, and no rich result is generated. The generator lists what is still missing rather than quietly producing markup that will never do anything.
The other half of the job is honesty. Structured data has to describe what is visible on the page. Marking up questions that are not there, or a price that is not shown, is what the spam policies on structured data exist to catch, and a manual action is much harder to reverse than it was to cause.
Where the markup goes and what to check
Paste the block into the head of that one page. In WordPress the plugin or theme that manages your head section will have a field for it; do not put it in a global header, or every page will claim to be the same thing. If your site already outputs schema of the same type, remove one of them rather than shipping two competing descriptions of the same page.
Then confirm it with Google’s own Rich Results Test and the Schema Markup Validator before you rely on it, and watch the enhancement reports in Search Console over the following weeks. If you would rather have it built into the templates so it stays correct as pages change, that is what the schema markup service does, and it is checked as part of every technical SEO engagement.