Are the contacts Outlook contacts, or MS Exchange contacts (i.e., in the Active Directory)?
If they're in the AD you'd use Get-Contact and Set-Contact cmdlets, or Get-MailContact and Set-MailContact cmdlets.
If they're contacts created by mailbox owners you'll probably have to resort to using Invoke-RestMethod if the mailboxes are in Exchange Online (Example: https://gsexdev.blogspot.com/2014/04/oneliner-mailbox-access-in-powershell.html). If your Exchange is on-prem you'll some pointers here: https://www.undocumented-features.com/2019/07/16/some-of-the-many-ways-to-export-outlook-contacts/
Using Entra, you'll probably have to use the PowerShell Microsoft.Graph.Entra module.