Open Graph tags are added to your Website via Meta Tags.
The type of tags used should represent the content of the page. So, your home page tags would contain content about the site as a whole, and the tags on a page or blog post would focus on the content of that particular post.
The following four tags are required by Facebook:
Optionally, but recommended, you should add these additional tags:
Location of the these tags.
You’ll need to place these meta tags in the <head> of your HTML file. Don’t forget to substitute the values for your own.