@Larissa Kaur Thank you for posting your question on Microsoft Q&A.
Sorry to hear that you are not able to create WordPress on App Service for Canada central region from your MCPP Subscription.
Suggest you to create a support ticket with Azure Billing/Subscription management at https://azure.microsoft.com/en-ca/support/create-ticket/where support team will whitelist your subscription and that will allow you to create resources in that region. As Canada central region is available for creating Word press app service.
I have also reached you privately please let me know.