By default you can register @outlook.com , @hotmail.com and .tld from some countries
Some domains are not available for registration but existing email addresses continue to work and all MSFT email domains have equal rights.
For example, I own
xxxx@live.com,
xxxx@hotmail.com,
xxxx@outlook.com,
xxx@hotmail.co.il,
xxxx@outlook.co.il
I had
xxxx@msn.com but lost access to it at some point.