จะมอบอำนาจให้แฟนชาวต่างชาติขายบ้านพร้อมที่ดินในต่างประเทศให้ยังไงดีคะ

You must go to the US consulate in Thailand and tell an official staff that you would like to give a power of attorney to your spouse for the sell of the house. The staff will provide you a form to sign and the worker will make an official stamp with a signature. The document will be stapled with a special hole maker that will hold all the document/s which is/are not allowed to pull apart otherwise considered the power of attorney invalid. It will cost you a fee. You must bring a government photo ID (a passport).

You can provide your own written statement of what you want to give your spouse in USA a power of attorney to act on your behalf. Make sure that your statement covers everything so that it will save you a fee to have one power attorney for every thing. Try to limit one page to save the fee because it will cost money for each officer's signature to sign on each page.

I used to have my spouse in Germany to send me a power of attorney from Germany to USA that he had to have it done officially at the US consulate in Munich. It costed $35 for one signature and a US consulate stamp, that was many years ago.

DO NOT sign anything on your written statement before seeing a US consulate staff, you will sign in front of the staff and you will provide a government photo ID to the staff to prove it.