Recently I had to perform a task in which there was a need to change UserName, Alias and SMTP addresses associated with the user for approx 150 users. These were recently created users.
If I start doing it using GUI, am sure my whole day will pass in find, click.. click.. click..
I had to do little bit of manual work like generating a csv output for the users in the department OU and add new username and new email address column to it.
The final CSV looked like this. 
Once ready with the csv file, lets import it in PowerShell and let it do its magic.
$userCol = Import-Csv -Path C:\Update-users.csv
Foreach($user in $userCol){
"Processing : "+$user.UserName
Set-Mailbox -Identity $user.UserName -EmailAddressPolicyEnabled $false
Set-Mailbox -Identity $user.UserName -Alias $user.NewUserName
Set-Mailbox -Identity $user.UserName -EmailAddresses $user.NewEmail
Set-Mailbox -Identity $user.UserName -EmailAddressPolicyEnabled $true
"Changing UserName from: "+$user.UserName+" TO: "+$user.NewUserName
Set-Mailbox -Identity $user.UserName -SamAccountName $user.newUserName -UserPrincipalName $user.upn -Alias $user.NewUserName
}
I did use a seperate set-mailbox for each task for easy to understand.
The script is self explanatory.
Hope it helps.
vHomeLab 
How to update the country for the user profile in AD. If you have a list of users who are from different country and country need to update in AD. this scenario happens when creating new joiner accounts of different region.
So do know how to use powershell to update country, when creating new joiner accounts.
Hi!
If you have got the list of users in a CSV format, you can add a new column to it as “country” and fill in the appropriate country for user under the new column.
import csv file as done in the above script, and use Set-ADUser cmdlet with -country parameter.
Refer https://docs.microsoft.com/en-us/powershell/module/addsadministration/set-aduser?view=win10-ps
All other properties like Street, address, zipcode, updates but does not update country. if you have test environment, please do test.
Did you use Country abbreviation or Country name as value? you must use abbreviation.
e.g., Set-ADUser -Identity TestUser01 -Country “BH”
Here is my complete powershell code, it works for all attributes, but not for country.
I could not add the excel sheet, Hope you will take dig into this code.
# Import AD Module
Import-Module ActiveDirectory
write-Host ‘Starting to update AD Attributes…….’ -NoNewline -ForegroundColor Yellow
# Import CSV into variable $users
$users = Import-Csv -Path C:\temp\users.csv
# Loop through CSV and update users if the exist in CVS file
foreach ($user in $users) {
#Search in specified OU and Update existing attributes
Get-ADUser -Filter “SamAccountName -eq ‘$($user.samaccountname)'” -Properties * -SearchBase “DC=ittechsolution,DC=com” |Set-ADUser -Country $Country }
#Set-ADUser -Office $($user.Office) -OfficePhone $($user.officePhone) -MobilePhone $($user.MobilePhone) -fax $($user.fax) -Title $($user.Title) -Department $($user.Department) -Company $($user.Company) -Manager $($user.Manager) -StreetAddress($user.StreetAddress) -City $($user.City) -State $($user.State) -PostalCode $($user.PostalCode) -Replace @{IPPhone=$User.IPPhone} -add @{OtherTelephone=$user.OtherTelephone},-Country $($user.Country)
}
Write-Host ‘done!’ -ForegroundColor Green
The problem that I see is, you are importing user accounts to be processed from CSV as well as retrieving users using “Get-ADUser” within Foreach loop.
This is how my CSV looks.
“Name”,”samaccountname”,”Country”
“Lab User A”,”labusera”,”BH”
“Lab User B”,”labuserb”,”IN”
“Lab User C”,”labuserc”,”US”
“Lab User D”,”labuserd”,”UK”
#—Script—
$users = Import-Csv -Path C:\reports\userlist.csv
foreach($user in $users){
#SAMAccountName should be in CSV
Set-ADUser $user.samaccountname -Country $User.country
}
#check Output
Get-ADUser -Filter * -Properties * | where{$_.Name -like “Lab*”} | select Name,SamAccountname,Country
#—Output—
Name SamAccountname Country
—- ————– ——-
Lab User A labusera BH
Lab User B labuserb IN
Lab User C labuserc US
Lab User D labuserd UK
Hope this helps.