Facebook pages need certain criteria to be eligible for custom URLs
But with a simple technique you can set your URL in no time . For this you need 2 Facebook account
1. From which you create this page
2. A separate account , from which this page is liked
Now login to the first page and make this second account admin of that page
Logout and login to the second account , open this page and go to settings on top right . Click on about and set username right from here .