Just search twitter or twitter.com and you will see this page ( see ref. image below ) if you already have signed in or account in twitter.
In my case , I set my username to saranshsagar999, You can see I highlighted two things one is my username and other is Setting & Privacy Policy page in red rectangular frame. Click on Setting & Privacy Policy Page . One can also go to this page if they know or bookmark this link.
Now you will see this page where you can easily see that where you have to set your custom username as per your requirment,wishes !!
Click on this username section or move to down for save your custom username .
Har Har Mahadev !
Tags – How To Change Your Twitter Username,Change My Twitter Username,Change Twitter Username,Twitter Username
