Formal:
* ขอบคุณมาก (Khop khun mak) - This is the most common and polite way to express gratitude.
Informal:
* ขอบคุณ (Khop khun) - This is a more casual way to say "thank you," but it's still polite.
* ขอบคุณมากๆ (Khop khun mak mak) - This is a more emphatic way to say "thank you very much," but it can be a bit too informal for some situations.
Other options:
* ขอบคุณครับ/ค่ะ (Khop khun krap/kha) - These are the polite forms of "thank you" that are used by men and women, respectively.
* ขอขอบคุณ (Khor khop khun) - This is a more formal way to express gratitude, often used in written or spoken communications.
You can also add "มาก (mak)" to any of these expressions to emphasize your gratitude.
Here are some examples of how to use these phrases in a sentence:
* ขอบคุณมากสำหรับอาหาร (Khop khun mak samrap ahan) - Thank you very much for the food.
* ขอบคุณสำหรับความช่วยเหลือ (Khop khun samrap khwam chuai luer) - Thank you for your help.
* ขอขอบคุณสำหรับเวลาของคุณ (Khor khop khun samrap welah khong khun) - Thank you for your time.