@Ndechi Maro Greetings!
To transfer Azure credits to other account (subscription), you need to contact Azure billing team by raising a support request and request for Azure credits transfer. The ticket enables you to work closely with the support engineers and get a quick resolution to your issue.
Here is the link - https://docs.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request to create support case.
FYI: Azure Billing and Subscription Management support is included in the Basic Support Plan without any charge.
https://azure.microsoft.com/en-us/support/plans/
Refer to the Azure Credits & Billing FAQs
Hope this helps. Please write back to us if you have any questions.
If the response helped, do "Accept Answer" and up-vote it