You can't change it.
What you can do is buy the additional extensions.
You go to a company that sells domain names, or in other words a "registrar" and you buy the domains with the TLD (the stuff after dot) you want. Usually, it's a yearly fee.
I prefer and recommend namecheap.com, you can see here what TLDs they offer: https://www.namecheap.com/domains/registration/results.aspx?domain=animalastral.com
Once you have the domain purchased (or "rented") you can link the domain name to a website or a server (you make the connection between animalastral.com and an IP like 220.127.116.11
You then configure the server that serves the page to also serve the content when it's loaded from that new domain.
Alternatively you can configure a DNS entry which tells any browser to simply redirect to animalastral.COM when the new domain is entered.