Help is here.

Yes, you can. 

When you publish your site for the first time, your site address is in the form of a free Wix URL: accountname.wixsite.com/site-name.

You can change your free Wix URL by editing the account or site name:

By changing the account name, you can change the first part of your free site URL: accountname.wixsite.com/site-name

To change the account name, follow these steps: 

1. Go to Account Settings in your Wix Account.
2. Click anywhere in the account name field.
3. Type in your new chosen account name in the pop-up that opens.
4. Click Save.

By changing the site name, you can change the last part of your free site URL:  accountname.wixsite.com/site-name.

To change the site name, follow these steps: 

1. Go to your site's Dashboard.
2. Click Site Actions.
3. Select Rename Site.
4. Type in your new chosen site name. 
5. Click Save.