Aragorn is the Middle-earth character known as Strider before being revealed as a king.
Aragorn first appears in The Lord of the Rings as a mysterious Ranger at the Prancing Pony in Bree. He protects the hobbits on their journey and is initially known by the name Strider. His identity is gradually explained as the heir of Isildur and a descendant of the kings of Gondor and Arnor.
Aragorn is the son of Arathorn II and Gilraen. He spends part of his youth in Rivendell under the protection of Elrond, who gives him the name Estel, meaning “Hope.” After the War of the Ring, Aragorn becomes King Elessar and marries Arwen.
Strider is therefore not a separate character from Aragorn. It is a name connected to his life as a wandering Ranger. Boromir and Faramir are important men of Gondor, but neither is the hidden heir who becomes king.