How hyperlinks work inside a PDF

A clickable link in a PDF is not part of the text — it is a separate rectangle laid over the page that triggers an action when clicked.

Link annotations

Each link is a link annotation: a rectangle plus an action. The rectangle defines the clickable area; the action says what happens.

Two common actions

• URI — open a web address in the browser.
• GoTo — jump to another page or position in the same document, used for tables of contents.

Why links sometimes break

If text moves but the link rectangle does not, clicks land in the wrong place. Good tools keep the rectangle attached to the content it labels.