What it does
It does not boost rankings by itself. It helps Google understand your business and can make pages eligible for rich results such as FAQs, breadcrumbs or job listings.
Types worth using
LocalBusiness (or a more specific type) on your home or contact page with name, address, phone, hours and service area. Service on service pages. FAQPage where a page has real questions and answers. BreadcrumbList for navigation. JobPosting if you hire.
The rules
Markup must match what visitors can see on the page. Do not mark up reviews you do not display or invent ratings. Misleading markup can lead to a manual action.
Test it
Use Google's Rich Results Test and the Search Console enhancements reports to confirm the markup is valid and eligible.
Keep it current
When your hours, phone or services change, update the markup along with the page.
Common questions
Can I add schema with a plug-in?
Yes, many plug-ins do. Check the output, because defaults are often wrong or incomplete.
Will FAQ schema show in results?
Google limits when it shows FAQ results. Use it where it helps readers, not to chase a display.
This guide is general information. Search engines change how they work and their guidelines; check Google's current documentation for your situation. Nobody can guarantee a ranking.