Скачать или смотреть How to change your X (Twitter) username Id

How long can usernames and names be?
Your username must be more than 4 characters long and can be up to 15 characters or less.

Your username can contain only letters, numbers, and underscores—no spaces are allowed.

Your display name can be up to 50 characters long.

How to change your username
Step 1
Click on the More button from the navigation bar.

Step 2
Click on Settings and Privacy.

Step 3
Click on Your account.

Step 4
Click on Account information.

Step 5
You will be prompted to type in your Twitter account password to confirm it’s you.

Step 6
Under Account information, update the username currently listed in the Username field. If the username is taken, you'll be prompted to choose another one.

Step 7
Click the Save button.