Google is your friend: Be nice and visit him often. He can answer questions a lot more quickly than posting them here...
A very quick search gave nearly 12 million hits:
Google "create database c#"[
^]
The first link is a tutorial from MSDN!
https://support.microsoft.com/en-us/kb/307283[
^]
In future, please try to do at least basic research yourself, and not waste your time or ours.