Please make sure you are in the Classic Interface.
You will need a Experian Address Validation Licence to be able to use this function.
Activate Experian Address Validation to enable end users to validate global addresses within Microsoft Dynamics 365. To do this:
1.Log into Microsoft Dynamics 365.
2.From the main dashboard drop-down menu, click Settings, and then Solutions.
3.In the All solutions window, click the Experian Data Quality for Microsoft Dynamics 365 display name to open a new window.
4.In the left panel, click Configuration.
5.In the Activation tab, check the Experian Address Validation box.
6.Fill in the In the Experian Address Validation box.
7.Click Apply in the bottom-right corner.
8.Click the Close icon of the pop-up window to exit to the All Solutions Dashboard..