Anchor text is the visible text of a link, the words between <a> and </a>. Google writes in the SEO Starter Guide that link text tells users and Google something about the page you link to, before anyone has clicked on it.
In its link guidelines, Google asks for anchor text that is descriptive, concise and relevant to the page it appears on. If an image is the link, the image’s alt text serves as the anchor text.
Example
<!-- Vague -->
For our rates, <a href="/rates">click here</a>.
<!-- Descriptive -->
See the <a href="/rates">rates for roof repairs</a>.In the second example, a reader knows what they will get before clicking, even without reading the surrounding text, like someone going through the links on a page with a screen reader.
Why does it matter?
The anchor text of internal links helps search engines understand what a page is about. According to Google, link text on other sites that points to your page is also one of the sources for your page’s title in search results.
Common mistake
Stuffing every link with keywords, such as “cheap roof repair Apeldoorn roofer Apeldoorn”. That reads badly, and filling pages with keywords to manipulate rankings is keyword stuffing under Google’s spam policies. Simply describe where the link goes.
See also backlink.