The discovery was made shortly before 3am on Monday after officers attended a lay-by on the Bridgnorth Road, close to Perton, near Wolverhampton, following reports of suspicious activity.
The Staffordshire force said in a statement: “On arrival officers found a woman who was sadly deceased. It was apparent she had been set alight at the location and had significant burn marks on her body.
“We are conducting multiple enquiries, but it is vital that we identify this young woman as soon as possible.
“At this stage we can only say that she is of slight build and believed to be aged between her late teens and 30. We are working to identify her through forensic testing.
“If you believe you may know who she is please get in touch with us.”
Anyone who was in the area of Bridgnorth Road between 1am and 3am on Monday is also being urged to contact detectives.
Detective Superintendent Tom Chisholm said: “We believe the young woman was driven to the site.
“Did you witness anything or have local dashcam or CCTV footage? Are you aware of any girls or women who are missing or unusual activity in the area Sunday night into the early hours of Monday morning.
“This was a shocking and dreadful incident and we are determined, with your help and support, to bring those responsible to justice. We will provide further updates as soon as we are able to do so.”