In more detail
In the HTML <a href="https://example.com/pricing">see our pricing</a>, the words "see our pricing" are the anchor text. Google's guidance on making links crawlable recommends anchor text that is "descriptive, reasonably concise, and relevant to the page that it's on and to the page it links to". It suggests avoiding generic text such as "click here" and avoiding long strings of keywords.
Anchor text matters in two places. On your own site, internal links with clear anchor text help search engines understand which page covers which topic, and help visitors navigate. On other sites, the anchor text people choose when they link to you is one of the signals that describe your page to search engines.
There's a well-known risk here. In the past, sites manipulated rankings by building many links with exact-match keyword anchors, such as "best cheap car insurance". Google's spam policies list links with optimised anchor text in articles or press releases distributed on other sites as an example of link spam.
Why it matters when hiring an agency
Ask how an agency approaches anchor text in link building. A natural backlink profile has varied anchors: your brand name, your web address, descriptive phrases and occasional generic text. An agency that asks publishers for exact keyword anchors on every link is creating a pattern that looks manipulative.
Internally, though, descriptive anchors are good practice and fully under your control. An audit that improves internal anchor text on key pages is often a quick, low-risk win.