Foreigners cannot own land in Thailand (this is illegal under Thai land laws) and foreigners are not mentioned in a sale contract involving land. Foreigners could be indirectly involved in a sale and purchase of property in Thailand because they for example finance the deal when land and house in bought on the name of a Thai spouse or Thai partner or friend.
This Thai English sale and purchase contract for real estate (land and house) contains the following contract headings:
The zip file contains printable and editable office word documents including instructions.