My Icloud is connected with my bothers Iphone. How do I change it?

I always receive my brothers texts on my my mac through iclood. Is it possible to change it so its configured to my phone?

Added (1). @JohnAiken… Could I possibly change the number on the Apple ID?

You need to get a new apple ID. You are getting his texts because you have the same ID, which pretty much shares all of the information between apple devices. Unfortunately, this is the only way to do this, unless you just turn off the texting feature on you mac.