Hello @Brent Mills ,
Hope you have chosen Authentication Type as Password instead of SSH Public key at the time of VM creation ?
You can find the username by using the below command:
(Get-AzVM -ResourceGroupName <resourcegroupname> -Name <VMname>).OsProfile.AdminUserName
Once you have the username , you can reset the password of that user using the Reset Password option from Azure Portal VM options.
(or)
You can use the same view to create a new user and new password
Regards,
Shiva.