Your Skype Name (also called Skype id) is a unique user name that many people use to sign in to Skype.
You created one when you first signed up for your Skype account.
You may also use a Microsoft account to sign into Skype ( which is an email address) or a Facebook account.
Your Skype Name can be between 6 and 32 characters. It starts with a letter, and can contain only letters, numbers and the following punctuation marks:
Once you've created a Skype Name, you can't change it.
How to find your Skype Name on your device ?
Read this help from Skype support : https://support.skype.com/en/faq/FA10858/what-is-a-skype-name-and-how-do-i-find-mine