Symbolism, Imagery, Allegory
The first section of this story involves what Benjamin Franklin said were the only two certain things in the world: death and taxes.
Miss Emily's death at the beginning of the story, and the narrators memory of the history of her tax situation in Jefferson might be what Alfred Hitchcock called "macguffins." A macguffin is "an object, event, or character in a film or story that serves to set and keep the plot in motion despite usually lacking intrinsic importance" (Source). Neither the funeral nor the tax issue seem to be all that important to the tale of murder and insanity that follows.
But that doesn't mean they lack symbolic value.
The taxes can be read as symbols of death. The initial remission of Miss Emily's taxes is a symbol of the death of her father, and also a symbol of the financial decline Emily's family experienced. It's also a symbol of Emily's father's continued control over his daughter....even from beyond the grave.
And, when the "newer generation" tries to revoke the ancient deal they inherited, taxes are still a symbol of death, though this time, they symbolize the death of an older way of life. Miss Emily's tax deal was created because of the dual forces of chivalry and sexism: chivalry, because the tax remittance allowed Miss Emily to stay in her father's house, and sexism because such a deal was only necessary because it was impossible for Miss Emily to work and support herself.
When the townsfolk show up to claim back taxes, they're effectively informing Miss Emily that her role has fundamentally changed. She's no longer a helpless genteel woman; she's now just another citizen who needs to pay the IRS.
Of course, Miss Emily chases away the would-be tax collectors, much in the same way that she keeps modernity at bay by holing herself up in her father's house and snuggling with a corpse. Sometimes, the best thing is just to accept change—but nobody ever told Miss Emily that.