Drupal - How to get the url of a file field of a given node?
First you need to load it with the fid :
$file = \Drupal\file\Entity\File::load($fid);
And after :
$imageSRC = file_create_url($file->getFileUri());
It is also possible to do one-liner with magic method:
$node->field_file->entity->getFileUri();
Or to render as string
Option 1: $node->field_file->entity->url();
Option 2: file_create_url($node->field_file->entity->getFileUri());