Sometimes, you may need to add or remove certain fields to Outlook contact cards such as Mobile number, Address, …
These fields are managed by the Global Address List (GAL). In order to make changes in the Global Address List, you must use the Details Template Editor located in the Exchange Toolbox MMC.
Go to your Exchange server, and open the Details Template Editor
Locate the details for English Users for example, and double-click the en-US\Usertemplate
Select the field you want to remove and press DELETE. Save this form: File -> Save
Now, wait a moment to replicate the changes then close and reopen your Outlook.
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