Get API for media

I am using v4 and managed to call GET and return all the text content of the list and single entry. But i added a field “attachment” and uploaded a PDF to one entry. When i call the GET again, the attachment field is never show in API.

How can i get the attachment too?

You have to use populate to get data from media fields:

The REST API by default does not populate any relations, media fields, components, or dynamic zones…