Do you know anything about the designer Donna Karen?
Yes, I do.  She is an american fasion designer and creator the DKNY clothing labels.  She's quite famous.
Where do they sell her clothing items - in malls or more upscale places?
She sold the company in 2001 to Louis Vuitton Moet Hennessy.  Her clothing was typically found in malls
So does she still design or is she out of the business?
LVMH has 60 subsidiaries.  DKNY is one of them but, Donna Karan is not designing for them anymore
Does she do dresses for the stars, like on the runway for events like the Grammy's?
Not so much anymore.  Since 2015 she's really been focused on her Urban Zen brand and foundation.
I've never heard of that brand - is it more casual?
DKNY
DKNY is a New York-based fashion house specializing in fashion goods for men and women, founded in 1984 by Donna Karan.
History.
Karan worked for 15 years at Anne Klein, including 10 as its head designer. In 1984 Karan and her late husband Stephan Weiss were offered the opportunity to start their own business by the owner of Anne Klein, Takihyo LLC.
The company became a publicly traded venture in 1996.
In 2001 it was purchased by the French conglomerate corporation LVMH (Louis
Vuitton Moët Hennessy). In 2015 Donna Karan left as chief designer at Donna Karan International, to focus on her Urban Zen brand and Urban Zen Foundation philanthropy. LVMH sold Donna Karan International, with the 'Donna Karan' and 'DKNY' brands, to the G-III Apparel Group in 2016 for $650 million. G-III, based in New York City, is a manufacturer and distributor of clothing and accessories under their owned brands, licensed brands, and private label brands.
Donna Karan New York