Schema markup is a block of code in the page that a visitor never sees. It states plainly what the page is: this is a local business, this is its phone number, these are its opening hours, this is a question and this is the answer. Google reads it instead of guessing from the words.
What it is worth to a trade
It does not rank you higher on its own. What it can do is make your result look different in the search listing, for example a set of frequently asked questions shown under your link, and it makes your business details machine readable for the map results.
Google publishes what is supported and what the rules are in its structured data gallery. If a type is not in there, adding it does nothing.
A worked example
A roofing site had its phone number, address and opening hours in the footer as ordinary text. Correct, readable, and invisible as data.
Adding LocalBusiness schema to every page stated the same details in a form search engines read directly, so the number, area and hours matched between the site and the Google listing exactly. It is the tidying up job that makes everything else you do agree with itself.
The one rule
The markup must match what a human sees on the page. Marking up reviews you do not display, or services you do not offer, or star ratings you have invented, is against Google's guidelines and gets the whole thing ignored or penalised. Never add star ratings to your own pages about yourself.
Why it matters for your site
Check these on your own site
- LocalBusiness schema on every page keeps your details consistent for search engines.
- FAQ schema can put your answers under your result in the listing.
- The data must match the visible page. Never mark up something that is not there.
- Never invent review scores or star ratings in schema. It is the fastest way to a penalty.
- It supports your ranking work. It does not replace it.
Common questions
Does schema markup improve rankings?
Not directly. It helps search engines understand the page and can change how your result looks in the listing, which can improve how many people click it.
What schema should a trade website have?
LocalBusiness or a more specific business type with your real name, number, area and hours, plus FAQ markup on pages that genuinely show questions and answers.