I need to know their office address, please help me.

https://gmtmarkets.com.au/

GMT Markets is the trading name of GMTK Global Pty Limited, a company authorized and regulated by the Australian Securities and Investments Commission (ASIC) with a Australian financial services license: 400364.

As for the question you asked, we indeed found a company address on the broker's website. But we still recommend that you ask the official customer services for a more accurate answer. For more details on this broker, please check our full GMT Markets review.