embellishment
A decoration or extra detail that makes something look nicer.
An embellishment is a decoration or extra detail added to make something more interesting, beautiful, or impressive. When a musician adds trills and flourishes to a simple melody, those are embellishments. When an artist draws fancy borders around a picture or adds decorative swirls to letters, those decorative touches are embellishments.
The word also means exaggerating or adding fictional details to a story. If you caught a fish and it was actually twelve inches long, but you tell everyone it was two feet long, you're embellishing the truth. When someone embellishes a story about their day, they might add dramatic details that didn't really happen, or make small events sound more exciting than they were.
Embellishments aren't always bad. A plain cake tastes fine, but frosting flowers and sprinkles are embellishments that make it special for a celebration. Architecture often includes embellishments like carved details, decorative columns, or ornate doorways that make buildings beautiful, not just functional.
Sometimes embellishment helps, and sometimes it hurts. Adding creative details to your fictional story is a kind of embellishment. Adding made-up details when recounting what actually happened is a kind of embellishment that can cross into dishonesty.