how to add keyword "-official site" at the google search

When we search some big company using google, you'll find most of the big company has keyword " XXXX- official site"

such as Macy's
when you google it,

it will show "Macy's - official site.....etc"

but when I search my website, it only shows my company name, where can I add the keyword " official site"?
so that customer will know this is some kind of "BIG" company.

Thanks.

Hi Silkcamel,

This things are acheived with seo.
You can add meta title for your home page as
Store name - official site

After certain days if your site is live you will yourself see above meta title for your home page url.
You can also write meta title for products, categories, etc

If you have multi language site then you can check this All in one seo module as well.
It has maximum seo features at least price.

Hi imdevlper18,
Thank you so much.