Unofficial biography, made by me. Contains lots of spoilers for the series. I will make a spoiler-free biography soon. Largely incomplete.

Name: Azusa Miura
Age: 22
Birthday: July 19th
Eye Color: Carmine
Location: Kyoto (moved from Chiba, for a new future)
Hair color: Blue
Favorite color: Violet
Personality: Elegant and refined
Pronoun: Watashi
Voice Actor: Nozomi Higetsu (緋月 希)
Debut Episode: Season 1, Episode 1
Nicknames: "Azusa-san" (Takane), "Azusies" (Akane), "Onee-chan" (Matsu)
Current status: Alive
Name Meaning: Her first name is written in hiragana, but can be written in kanji too, with its meaning as catalpa (梓). Her last name means three (三) and inlet (浦).

Azusa Miura is a 22 year old young freelancer artist, who is known for making beautiful classical and Japanese-style paintings, her favorite hobby. Ever since she was really young, she had been painting. She has made quite a lot of money making art commissions, from fellow friends and strangers.

Azusa also loves music, especially classical one. She goes to orchestra concerts often, and today wasn't an exception. She notices a silver haired lady named Takane Shijou make her debut in the orchestra, and Azusa was amazed by her violin skills. She talks to her, and then invites her to a tea party. She shows off her art pieces, which Takane loved to look at. After Takane tried making her own art piece, she learned she wasn't as good as Azusa. The two wanted to learn from each other, and agreed to teach each other in their expertise skills, and a beautiful friendship bloomed.

Azusa introduced her to her timid yet kind younger sister, Matsu. Matsu however hid; she was scared of Takane (she called her an alien). Azusa eventually convinces Matsu that Takane wasn't an alien, but Matsu was still scared of Takane Shijou. When Takane introduced her to her little sister, Akane, Akane tackled Azusa and then went crazy. Takane told her to calm down, but Akane wouldn't even listen to her big sister this time, making Azusa a little scared of Akane.

In the second season, a new artist named Mayumi Akiyama (秋山 真弓) moves from her native Shizuoka to Kyoto. While Azusa was touring a museum, Azusa and Mayumi meet. Mayumi becomes quick friends with Azusa, and together they did a collaboration art, which got lots of positive reviews, and helped Mayumi become popular.

Azusa Miura learns about the tragic accident of Chihaya Kisaragi, a teenage scientist who idolizes Takane Shijou, and dropped out of school. She personally never knew her, but Takane Shijou knew her (and even calls her a nickname, which is idolmaster). After learning of her death, Azusa Miura felt a little sad, but didn't have a meltdown, mainly because they never met.

Sometime between season 1 and 2, Azusa reunited with her crush in elementary school, and became friends. Eventually, they fall in love, and then get married. A daughter, Shizuka Hanayama (花山 静香), was born. Most of the times, her husband takes care of Shizuka, as Azusa is a little busy.

Facts

Her favorite food is traditional Japanese food.
Azusa Miura shares her name with a K-ON! girl, whose name is Azusa Nakano. She also shares her name with Azusa Tadokoro, who voices out Shizuka Mogami. Interestingly enough, Miura's daughter is also named Shizuka.
She is often emotional.
Her original name was Tsumugi Hamasaki (浜咲 紬, which means pongee beach blossom).