How to upload file (pdf) using raw in Postman?

Files can only be uploaded using the 'binary' and 'form-data' option. Postman considers raw data as a string.

Have a look at the documentation for a complete list of options Postman provides: https://www.getpostman.com/docs/postman/sending_api_requests/requests

You can choose the form-data upload. When adding a new form field, you can change the type of the field to "File". In Postman's current version (7.8) you have to leave the entry line and then move the mouse over the newly created entry to see this option.