Hi SamCook,
To get the all the user MFA registered details you need to use MSOL powershell Module.
In your PowerShell run this commands:
For All users:
Connect-MsolService
Get-MsolUser -All | Select-Object @{N='UserPrincipalName';E={$_.UserPrincipalName}},@{N='MFA Status';E={if ($_.StrongAuthenticationRequirements.State){$_.StrongAuthenticationRequirements.State} else {"Disabled"}}},@{N='MFA Methods';E={$_.StrongAuthenticationMethods.methodtype}} | Export-Csv -Path c:\MFA_Report.csv -NoTypeInformation
For Single user:
$user=Get-MsolUser -UserPrincipalName "******@xyz.com"
$user.StrongAuthenticationMethods
Let me know if this helps you.