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Drupal 8 - Media - File Media Type - Manage Form Display - Click Manage Form Display Tab

1. Click Manage Form Display Tab

Click the Manage Form Display tab.

Drupal 8 - Media - File Media Type - Manage Form Display - Completed Form Display Config

2. Reorder Fields

Drag your Mime Type and Size fields down into the Disabled section. The reason we do this is because these fields will be set up to be auto-filled when a file is uploaded.

Adjust the remaining fields as appropriate.

Click the Save button.