YouTube is rolling out Handles – just like we have for other social networks – in November. You will be notified via email when you can choose. Here’s a quote from the email
if you already have a personalized URL for your channel, we’ve reserved this for you as your handle. If you’re happy with that handle then you’re all set. If you want a different handle from the one we reserved, you can change it. If you don’t already have a personalized URL today, you’ll also be able to choose a handle. Keep in mind that handles are unique to each channel, so once a handle has been chosen, it can’t be selected by anyone else.
But what are handles you might ask. From their help page on the subject youtube.com/handle
Handles are a way for you to find and connect with creators on YouTube. Handles are unique and short channel identifiers separate from channel names, and they start with the “@” symbol. For example, @youtubecreators.
And most importantly
If you don’t select a handle by November 14, 2022, YouTube will automatically assign you one. You can change this handle at any point.