How do you get PowerShell to ignore blank CSV values?

I'm writing a script that is supposed to update each attribute in Active Directory based on a CSV file. This is what I have so far:

$employees = Import-Csv -Path .\ADFieldsTest.csv
foreach ($User in $employees)
{
    $Username = $User.username
    $Department = $User.department
    $Displayname = $User.displayname
    $Fax = $User.fax
    $Manager = $User.manager
    $Mobilephone = $User.mobilephone
    $Officephone = $User.officephone
    $Title = $User.title
    $server = $User.server

    Set-ADUser -Identity $username -Department $department -DisplayName $displayname -Fax $fax -Manager $manager -MobilePhone $mobilephone -Title $title -Server $server
}

It kind of breaks when it reaches a cell that is blank in the CSV.
Is there a way to get PowerShell to just pass a "null" value or something so it keeps running?

I also tried running this with like !null values and like -nq '' but it still fails when it hits the the blank values

There isn't a way of telling Import-Csv to not create properties for empty values, the validation has to be done in your loop. You can use String.IsNullOrWhiteSpace(String) Method to validate and skip empty values and create a splatting hashtable to use with Set-ADUser.

Also, since your CSV columns seem to have the exact same names as the Set-ADUser parameters, you could avoid doing multiple if conditions and replace the logic with an inner loop.

foreach($User in Import-Csv -Path .\ADFieldsTest.csv) {
    if(-not [string]::IsNullOrWhiteSpace($User.username)) {
        # if there is no username then this line has to be skipped
        continue
    }
    
    $setSplat = @{}
    foreach($prop in $User.PSObject.Properties) {
        if([string]::IsNullOrWhiteSpace($prop.Value)) {
            # if the value is empty string then skip
            continue
        }
        $setSplat[$prop.Name] = $prop.Value
    }

    Set-ADUser @setSplat
}