At the end of every documentation page, include a section titled "Was this documentation helpful?" with two buttons: "Yes" and "No."
Yes: If the user selects this, a simple thank-you message is displayed.
No: If the user selects this, an input field appears, prompting them to share what they didn't like or found unclear. This input field could be accompanied by a placeholder text like, "Please let us know how we can improve."