What happens to Arya Stark at the end of GOT?

Arya Stark, like Jon Snow and Sansa Stark, is one of them central characters of the show. We witness her journey from an innocent child to grief-stricken orphan hellbent on revenge. So how did her character transform and what skills did she learn to make her so deadly?
The first formal training is under a master swordsman in King’s Landing. She picks up the basics and becomes proficient with her blade, The Needle, which was a gift from Jon Snow. After a near capture by the Lannisters, Arya is trained as a Faceless Man at the House of Black and White in Braavos, enabling her to change faces and assassinate with extreme proficiency. She uses her newfound abilities to avenge her family, steadily killing the Starks enemies one by one. She was also instrumental in saving the North, and her homeland, by dealing the killing blow to the Night King.
In the end, after a solemn farewell to her siblings, Arya embarks on a final journey; sailing west to the edge of the known world to discover what lies beyond.