Is there anything like this? Where the girl change or undergo character development and she become more outgoing or popular....

Preferably not too many episodes since sometimes I have some problem following too long dramas. I'm fine with any country :)

Thanks in advance!

You can try Fate to Love you (Original (Tdrama) , Kdrama, Thailand). The original is good, but I think the Korean version is the best. The male lead is a lot more likable.  Oh My Ghostess  and  Flower Boy Next Door also fits what you are looking for. 

You might also like My Introverted Boss, which is about a guy who becomes a little more outgoing after being an introverted recluse. 

I second Oh My Ghostess! The main character’s development is seamless.

In addition:

 Nobuta Wo produce (drama revolves around 2 guys helping an inteoverted girl to be more outgoing)

Scent of a woman

Kingyo club

Heart to Heart

The wallflower

Black Devil and White Prince (she literally has step to reinvent herself to be friends with everyone)


Movies: kimi ni todoke, Sunny, Our Times, midnight sun, 

 


You should definitely watch Gakkou no Kaidan (also known as The Girl's Speech). I have just started watching it and I think it somewhat fits your description. The female lead is a quiet girl that enters a school as the President of the Student Council, while being bullied and ostracized by others, but she eventually becomes braver and develops a voice with the help of the male lead. 

https://mydramalist.com/12190-gakkou-no-kaidan

movie:

Today's Kira-kun

From Me to You

Spellbound

drama:

Yamato Nadeshiko Shichi Henge

  

Cat street

Nobuta wo produce

Fated to Love you

Flower boy next door

High School Debut

Love for Beginners

Love Song

Oh my Venus

Paradise Kiss

Yamato Nadeshiko Shichi Henge

Miss No Good

Birth of a Beauty

Somehow 18, which is a brand new webdrama, shows a male version of this.  I just finished it so a thought i'd throw it in.  It is the focal point of the show and how it seriously affects others around him.   http://fastdrama.co/somehow-18

Kahogo no Kahoko  (overprotected Kahoko)

- Its about a girl who was overly protected/sheltered by her family, even in college she can barely do anything on her own. Then she meets a guy who will change her. I really love this you should really watch it!

Thanks, everyone! Gonna check them! :)

Skip beat

https://mydramalist.com/1736-skip-beat

the also an anime, but if you want full story read manga.