See this example properly formatted in the QUT Cite tool.
Standard in-text citation examples are in Getting started - In-text citation.
Author AA [username]. Title [Content form]. Place of publication: Publisher; Year Month Day [cited Year Month Day]. Available from: http://www.xxxxxxx.xxx.xx
 CSIRO [@CSIROnews]. Eating enough fruit and vegetables lowers the risk of many chronic diseases [Twitter]. [place unknown]: CSIRO; 2018 Feb 5 [cited 2018 Feb 8]. Available from: https://twitter.com/CSIROnews/status/960332146282971136
 CSIRO. This is Gale crater, likely once a lake but now dried up, it gapes an enormous 154 km in diameter and would span half the distance from Sydney to Canberra [Facebook post]. [place unknown]: CSIRO; 2018 Feb 5 [cited 2018 Feb 8]. Available from: https://www.facebook.com/CSIROnews/posts/10155543297473843
Cite social media posts as you would a web page.
Social media that is not publicly accessible due to privacy settings are cited as personal communication.
Include the archival URL when possible (click on the post's date stamp) as it is the most accurate and reliable.
Use the name of the page, content or caption of the post (up to 40 words) as the title.
If the author's name is not provided on the source, use their username.