The fire in South Street, Braintree, began at about 22:30 GMT on Wednesday, trapping Alina Kordaszewska and her daughter Emilia, 11, inside.
Dozens of floral tributes have been left outside the property which is still being guarded by police.
More than 100 people gathered at the town's Catholic church on Thursday night for a special mass.
The cause of the fire is still being investigated by Essex Police and the fire service.
Neighbour Claire Deloubes told of screams and vain efforts to break through a window to rescue those inside.
She said: "We heard screaming so we came outside and a woman was distraught.
"People were trying to break the front window but they didn't manage to."
Mrs Kordaszewska's other daughter Milena, 18, is understood to have been one of two women who escaped the fire.
The teenager's friends have set up a fundraising website page aimed at raising £5,000 for the family.
One card left outside the house on South Street reads: "Dear Alina and Emilia, May you rest in Peace, 2 angels in heaven."
Another message reads: "Emilia, you were the greatest friend anyone could ever ask for and one of the kindest and bubbliest people I have ever met.
"You will always be in my heart, gone but never forgotten."
Rafa Bogonos, who worked with Mrs Kordaszewska at CommScope in the town, said the deaths had "really hit our Polish community".
Notley High School, where Emilia had been a pupil, expressed its "unutterable sadness" at news of her death.
Her tutor described her as a "delightful, friendly and positive student" who had "settled in well during her first term" at the school.
A church service has been held in memory of a mother and her daughter who died in a house fire in Essex.