If you are bored with your old Twitter handle name and want to change it with a new and catchy one, so you don’t need to go anywhere, just follow the given below steps.
1. Visit your Twitter profile and scroll and click on the Settings and Privacy option
2. Click on the Your Account section
3. Then, tap on the Account Information option
4. Thereafter, you will see a lot of personal settings option
5. Click on your username and change it with your new name
Source: https://getassist.net/how-to-change-your-twitter-handle/