The IAT number is not directly related to the Visa Developer Portal, therefore, I will not be able to comment directly on how you will get the IAT number. Please contact the payer or person asking you to provide the IAT number for the significance of IAT.
To provide you with further assistance, can you please contact firstname.lastname@example.org and someone will work internally to help you find a point of contact that may provide you with further assistance.
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