What documents are needed to extend a 30-day visa on arrival in Thailand?

To extend a 30-day visa on arrival in Thailand, your friend will need to visit the immigration office in Phuket and bring the following documents: a completed visa extension application form, a passport with at least 6 months validity, a copy of the passport's main page and the visa page, a recent passport-sized photo, proof of onward travel (like a plane ticket), and possibly a fee for the extension. It's advisable to check with the immigration office for any additional requirements.