Question: Can two people be seen or known as the main character or can there be more than two?
You can tell a story from more than one point of view (POV), which essentially creates more than one main character, each with their own story arc.
In some multiple POV novels, one of the POV characters will be more fully developed and therefore be the main, main character.
In other novels, there may be more than one POV character who is fully developed.
Of course there are costs and benefits depending on what choice you make. The more POV characters there are, the harder it is for the reader to feel closely attached to any one of them. On the other hand, some stories (such as multi-generational epics) cannot be told from one POV alone.
With multiple POV characters, you have to decide how interconnected their various stories will be. Sometimes, they will all share an overall story throughline. In such cases, their separate throughlines will usually converge at the climax.
In other cases, their stories are completely separate and the only thing they have in common may be that they all live in the same community.