What documents do I need to prove prolonged residence in Thailand when applying for a visa?

The user is applying for a medical visa at the KL embassy but is confused about the requirement for proof of prolonged residence in Thailand for at least 6 months, specifically the need for a lease agreement. They currently do not have a signed lease as they want to wait for visa approval. Comments suggest alternatives like using an Airbnb or hotel booking that allows for free cancellation or providing documentation of clinic visits for their treatment. There are also a few inquiries about past accommodation arrangements related to the user's treatment.