"Train it on your website" makes it sound as though any website will do. In practice a bot trained on a thin site gives thin answers, and the owner concludes the AI does not work.
Here is what actually needs to be there.
The six that do most of the work
1. What you do, specifically. Not "quality service since 1998". The actual list of services, in the words customers use for them. "Boiler repair" beats "heating solutions" because that is what people type.
2. Where you cover. For any service business this is the highest-value sentence on your site. "We cover Greater Manchester and 15 miles beyond" lets a bot screen enquiries correctly at 11pm.
3. What it costs, or what decides the cost. Published prices are ideal. If you cannot publish them, publish the factors: "a rewire depends on property size, occupancy and whether it is staged". That is genuinely useful and it lets the bot ask the right questions.
4. Your process. What happens after someone gets in touch. First visit, survey, quote, timescales. This is the question behind most "how does it work" enquiries.
5. A real FAQ. The single highest-return page. Write down the ten questions you are actually asked and answer them plainly. Not the questions you wish people asked.
6. Credentials and reassurance. Registrations, insurance, guarantees, accreditations. It is what people check before booking.
How to write so it answers well
Use the customer's words. They search "blocked drain", not "drainage remediation". Retrieval matches meaning, but the customer's phrasing helps.
One idea per section, with a heading. Content is retrieved in chunks. A page where each section answers one question retrieves cleanly; a wall of text does not.
Be specific. "Same-day appointments where possible, typically within 4 hours for emergencies" is answerable. "Fast, reliable service" is not.
Say what you do not do. Underrated. It lets the bot decline politely rather than booking work you will have to hand back.
What does not help much
Blog posts. Useful for search, weak for answering. Marketing prose dilutes retrieval, which is why some products deprioritise blog content by default.
About-us history. Nobody asks.
PDFs of brochures. Usually image-heavy with little extractable text.
The useful side effect
Every item on that list also improves your website for humans and for search. If you write it and then decide against a chatbot entirely, you have still done the most valuable hour of work available to most small business sites.
Check what yours can answer
Build a bot from your site and ask it your ten most common questions. Where it struggles is exactly where your website is thin.