Malla is Chewbacca’s wife. In 1978, it was important to make it clear that Chewbacca was married to a female Wookiee to put a stop to any rumors about his relationship with Han. In 1978, it was also perfectly acceptable to leave your wife, child and elderly father home while you hang out with your buddies for months at a time without so much as a phone call.
Malla looks a lot like a female Chewbacca. She’s a slightly lighter shade of brown, and sometimes she wears an apron. Kenner created a prototype of Malla which was simply a Chewbacca figure with added boobs. The less said about that figure, the better. There are probably people out there that would purchase a Malla figure. I don’t feel like looking up to see if she’s been in any new canon sources, but maybe she’s important in some video game or something. I don’t know.