Windows PowerShell Command to New User Creation

Hi Team,

I hope, all of you are having Good Time. 

I'm looking for a PowerShell Command for new User Account Creation. I want the PowerShell Command to do the followings,

1. Add a suffix with user's Last Name if user with the same name exists. (Nothing about User Logon Name - that is always unique in my AD environment as we use employee ID's to create Login ID's ). 

For Example: A user (Paul Smith) already exists. If I create a new user with the same First and Last Name, it should suffix a numeric digit with the last name (Paul Smith1). 

2. If an AD Account already exists, it should write that in a file (Excel or Notepad), stating that"This User Account already exists." 

Warm Regards,

Manish

Manish Kumar