Add the field and customize the texts. Drag and drop the field to the form, and personalize the label and hint texts to your liking.
Set the number of files and their max. size. By default, it is configured to upload a single file up to 20MB but you can modify this in the field settings.
Select the allowed file types. Any type of file can be uploaded by default, although you can modify this option by selecting one or more types or extensions.
Publish and preview. Publish these settings and preview the form to check that everything is working perfectly.