Yes, we can change the URL “https://domainname.crm.dynamics.com/main.aspx”.

It is specific to the environment so, in order to change the name for an environment, you need to go to “Power Platform Admin Center” (“https://admin.powerplatform.microsoft.com”) and navigate to the environments tab and select the environment that you wish to update the domain name

Once you open the environment, you can see the “edit” option.

Once clicked on edit you will see a form will open on the left side where you can update the name and URL.

You can type in the name and URL that you want to use, for the URL system will check whether the typed-in URL is available or not. If available you can proceed and Save.