Please pick a subcategory to help organize the information. Thanks!
Also, the more context you provide with your questions (screenshots, link to an open app, etc.), the more likely you’ll get good help quickly 
You could use an API to get the data, or you can create a Data Table within your app
Found this API with a quick Google Search
Can you please tell me how can i create data table
Create a Data Type in your app, name it Currency Code or something like that, and include these fields
Code (text or maybe number)
Country (text)
You will then need to manually enter countries and their code, or upload a csv with the data