She is the production model of Doraemon (a prototype robot) and thus has various features that her brother lacked along with some improvements. She is also a lot lighter despite being only slighty smaller, weighing only 36 kg at a height of 100 cm.
Dorami was bought by Nobi Nobita's great-great-grandson Nobi Sewashi as a household robot after Doraemon was sent to aid Nobita in the past. She is usually portrayed as a somewhat overprotective sister, occasionally traveling from the future to bring Doraemon back for his maintenance.
As with her brother, Dorami also has a "Fouth Dimension Bag" with various gadgets from the future, albeit often with girly aesthetics. As per Sewashi's request, her "ears" was modified into the shape of large red ribbon in the hope that Doraemon would not feel inferior to Dorami for his own missing ears.