How to upload prc file type?

This article explains a method in which you can add a file type to the list of allowed file types.

Copy and paste the following code into your functions.php:

add_filter('upload_mimes', 'custom_upload_mimes');
function custom_upload_mimes ( $existing_mimes=array() ) {
    // add your extension to the array
    $existing_mimes['prc'] = 'application/x-mobipocket-ebook';

    // add as many as you like
    // and return the new full result
    return $existing_mimes;
}

I didn’t tested the code, but I hope it will help you along.