She debuted on September 18th, 2008. Her official facebook diposting the below image and wrote, "September 18th! Today is the 8th anniversary of #IU~ Stay together with iu from now on as well ♥×∞ Happy IU's 8th Debut Anniversary! #IU #UAENA".
iu has had hits after hits after hits and is one of K-pop's most talented singers. Congratulations to iu and her fan UAENA on her 8ths anniversary!
Source: link