If your google + profile has a display picture, has at least 10 followers, and is at least 30 days old then you can have a custom username or URL of your Google + Profile.
It's very simple!
All you have to do is visit your Google Plus profile (it's not your homepage, but your profile). Look for a notice there and hit "Got It"
Note : If you don't see it then be patient because Google is rolling out the feature slowly and it will be available to most users very soon.
Next thing is to agree and select your username and Hit change URL like in picture below
Now finally verify
Enter your phone number and click Verify, Voila! You're through! Now you have your own google+ custom URL like google.com/+YourName!