[Nfb-web] Removing power by WordPress

[Osman Koroma]

Hello, my name is Osman and I am a writer. I just build my website and I'm still working on it. I'm using WordPress. My question is how do I remove power by WordPress and put  my own copyright? The link to my website is below if you have any other suggestions I would greatly appreciate it. Thank you so much for your help. 
Please excuse any typos
Osman Koroma
www.osmankoroma.com
www.twitter.com/osmankoroma
www.facebook.com/osmankoromaauthor