The Nissan Cefiro she was driving become wedged under the truck, about 1km south of the Pekapeka wetlands.
Fire crews spent a number of hours cutting her body from the wreckage after the three-vehicle crash.
Ms Muller was the only occupant in the car.
A white ute following the Nissan was also involved in the crash. The driver of the truck was shaken but otherwise uninjured.
Cousin Stephanie Muller Pallares was very close with Ms Muller, especially growing up.
Her cousin was the one that always had a funny story to tell, could make people laugh and just feel comfortable, she said.
"She was the always up for an adventure and she would fight to the ends of the earth for the people she loved, that's why I will never forget her. The Mullers won't be the same without her," she said.
Tributes were flowing on Facebook for the 19-year-old Waipawa woman.
Friends said they were "honoured" to know her, calling her a caring friend who had high aspirations.
Another said she was now "heartbroken".
The fatality brought the 2016 regional road toll to six.
The first road fatality of the year was also from Central Hawke's Bay - Bradley Charles Dobby, 20, from Waipukarau who died on January 3.
There were two other road deaths in January - a two-year-old girl from Flaxmere and an 87-year-old man from Napier.
Ms Muller was the third to die on Hawke's Bay roads in February.
In one week a 75-year-old man died near Raupunga on February 2, and a 23-year old motorcylist died on State Highway 5, just north of Napier, on February 7.
