What are some good tips or ways to describe a character in a story that plays no significant role, and only appears for that particular moment in the chapter and never again for the rest of the story? What details are best to be mentioned in this case?
Agreeing with @RobtA, I would probably try to describe that person in a way that simply highlights "their role" in the scene. If they are in a scene, they serve a purpose. Use that! Focus on the part of that character that is or could be relevant for the reader.
If he's blocking a door or stealing an elevator, perhaps describe him as annoyingly unaware of his surroundings or selfishly busy - if that makes sense from the perspective(s) of your main character(s).
If he's doing a job, perhaps include simple details about how he's doing said job.
These descriptions, how insignificant they may seem, create opportunities for the reader to get to know the important character(s) better, based on the way they interact (or don't).
Jo Walton offers some thoughts on how to make the most of insignificant characters:
But say you have somebody bring the protagonist a drink. You don’t have room to make them interesting and flesh them out. Sometimes making them interesting would give them too much significance, draw too much attention to them. They’re still there. Say their story function is to say “Here’s your drink,” and distract the protagonist from their brooding so that they can go off in a new direction. The standard person would be—well, that depends on the setting. A barmaid, a waitress, a waiter, an innkeeper, old, young, human, alien, gay, straight, male, female—they’re not going to do any more in the story than put down that drink. But if they say “Here’s your drink, sir,” that’s one kind of person, and if they say “Here’s your drink, sugar,” that’s another kind, and you have a better story if you know what they say, even if that’s all they’re going to say before they disappear off the page, because the way the protagonist will be distracted from their thoughts will be different.
If the protagonist watches the old waiter staggering off with a tray and wonders how long he’s been doing that, gathering up glasses every night, and decides not to get into a rut like that? If the protagonist gets a sexual buzz from the server and really isn’t sure how to deal with that so gets up to leave? (Michel Tremblay has a great book called The Black Notebook about a waitress in an all night diner who’s a midget whose customers are almost all drag queens.)
Minor characters can provide the reader with a little more insight about the setting (what kind of people live in this world? What kind of people would be working in this building?), or about the main character (how does he/she respond to others, and how do others respond to him/her?).
Depending on the world and character you're trying to build, minor characters can be really useful tools for getting information across. If it's a near-future sci-fi, talking about what kinds of gadgets people play with while they're waiting for the bus and what they're wearing could tell the reader about the world, even if they don't actually do anything in the scene. If your story is set in 1930s Berlin and your main character is sitting in a café and spots someone at the next table wearing a star of David armband, he or she might remark that this person is a) Jewish scum or b) an unfortunate soul. That tells the reader a lot about the main character's attitudes, even if we never see that armband-wearing person again.
Your minor characters can be just as useful as anything else in your story – consider making the most of them wherever you can.