@Aditi Mokashi Thanks for posting your questions in Microsoft Q&A, apologize for any inconvenience caused on this.
Based on the shared I understand that you are taking about this "Get foreign exchange rates " in Partner center, if yes and also if your application is also hosted on Azure app service then you call the Partner center Rest API through Http call.
Also, I see this foreign exchange rates uses Partner Center Authentication which interim uses Entra Id authentication only. You can refer to samples here on how to authenticate to partner center via code based on your suitable programming language
If you want to know more this partner center Rest API, I suggest you reach out to Partner center community here as this is not supported in Microsoft Q&A forum here.
Hope this helps, let me know if you have any further questions on this.