A tale about a mother (1963)

The events take place during the Great Patriotic War.
The mother is illiterate, unable to read or write, but since the only way to stay informed is to wait for and read letters from the front, she begins to teach herself and eventually becomes a postwoman.
More than once, she has to deliver tragic news to other families, and she takes upon herself the burden of compassion for the mothers, understanding their grief and trying to ease it.