Anchor text is the clickable wording of a link. When a page says read our guide to tenancy deposits and those words are the link, that phrase is the anchor text. Search engines read it as a label for the page on the other end, so it tells them what that page is about before they have visited it.
Descriptive anchor text helps the linked page rank for what it says. Click here and read more tell Google nothing, and a site full of identical keyword anchors looks manufactured.
The text node inside <a href="…">. Google uses it, with the surrounding text, as a relevance signal for the target URL, for internal and external links alike. Image links use the image's alt as anchor text. Vary anchors naturally across a site: a mix of the page's topic, the brand and plain phrases. Exact-match anchors repeated across many external links are a classic manipulation pattern and have been penalised for over a decade.
Internally, anchor text is fully in your control and is the cheapest relevance signal you have. Link to the service page as the service, not as here. Avoid linking the same anchor to two different URLs, which blurs both, and keep anchors short enough to read as a phrase.
<a href="https://example.com/family-law/">family law solicitors</a> not <a href="https://example.com/family-law/">click here</a>