There were countless of lovable characters from The Office that had varying character arcs with some being very successful and others falling flat. Some characters wavered back and forth on their character arcs like Pam and Jim who finally got together but then had trouble in their relationship after marrying.
Some characters, like Michael, wanted to start families and did by the end of the series when he found his perfect match in Holly. Other characters barely changed at all, like Ryan and Kelly. However, every single main character had some sort of storyline and arc throughout the popular series.
Ryan
Ryan began the series as an optimistic business school student, who was just going to intern at Dunder Mifflin until he graduated, but everything changed with his character as the show continued. Ryan was hired full time and then given a promotion to work at corporate. However, his ego grew too much and he ended up getting fired from his position. Ryan never really changed or learned a lesson by the end of the series.
Kelly
Kelly had a similar story arc to Ryan, where she didn't really change much throughout the series. At Dwight and Angela's wedding, it seemed that maybe she had succeeded in moving on from her constant, unhealthy on-off-again relationship with Ryan as she showed up with a loving fiance and Ryan has a baby. But, Kelly hilariously ran off with Ryan, leaving his baby at the wedding, when she sees him.
Oscar
The finale shows that Oscar is getting ready to run for a Senate seat and he's become the godfather to Dwight and Angela's child. It shows a lot of growth for Angela and Oscar to be on such good since they were constantly fighting when they were working together.
Oscar's arc shows that he is finally pursuing something in line with his potential outside of the office and that he is a trusted and cared for member of the main characters.
Andy
By the final episodes, Andy actually seems to have calmed down and has good control over his anger - even after becoming a mass internet meme. He re his time at Dunder Mifflin fondly and misses it. After suffering from anger and self-confidence issues for most of the show, at least he found happiness in his job at Cornell. It's a nice if anti-climactic arc for him.
Jim
Jim's earlier story arc was trying to fight for Pam's attention and eventually marrying her. Although the slow burn took three seasons to happen, fans would still say it was one of the best and most romantic storylines.
However, in the later seasons, it wasn't exactly the perfect romance. In the latter half of the series, Jim was seen to make a huge career change as he ed Athlead. The issue was that his lies caused a massive strain on his marriage. Although the Pam and Jim arc was initially great, once he and Pam were married it seemed like he wasn't trying as hard in the relationship and his character seemed to falter a bit.
Pam
Pam had a similar story arc to Jim, but she also had an independent character arc. After ending her engagement to Roy, she found some freedom going to school and pursuing her love for art. Pam was also seen to become more independent and vocal too.
While Pam and Jim's marital issues marriage weren't that interesting to watch, there were some nice moments where she formed friendships with outside the main office. It was also a bonus to see in season 9 that Pam's artistic talents were recognized too.
Darryl
Darryl began the series as a very minor character who worked in the warehouse below the office and rarely interacted with the main characters. However, as the seasons went on, everything changed for Darryl. Darryl was always a hard, efficient, and safe employee who found great success in the warehouse, but still wanted more. He was promoted when his ideas were recognized in the office and eventually became incredibly successful at the sports marketing company, Athlead.
Angela
Angela had a similar story arc to Dwight on the show and it makes sense that the two were finally married by the end of the series. Angela appeared to be a very uptight and uncaring person in the office, but she grew to enjoy everyone's company - even if she showed it in the most unconventional ways.
Angela and Dwight seemed like a perfect couple before issues showed, but the two were thankfully able to work things out and she forgave him.
Dwight
Dwight had some good and some bad storylines. It took a long time to be able to show how much he truly cared about the people in the office, but he was finally able to by the end of the series.
Jim, his former work enemy, is his best man at his wedding and he and Pam have had multiple emotional moments together. Dwight is also able to figure things out with Angela and the two are married by the finale.
Michael
Michael's biggest dream and one of the driving forces of his character was wanting to fall in love and start a family. Even though he wasn't the most empathetic character and a little bit self-centered at times, this was one of his most endearing qualities.
While Michael had a couple of difficult time in his relationships, he finally found a perfect partner in Holly and Michael was able to move on from the office and begin his own little family.