Follow the below steps to add the related object Field Name to the downloaded File Name:

Step 1 - Create Formula Field

  • Go to the "Setup".
  • Take an example of Opportunity Object, Once files have been downloaded from the "Opportunity" Object, they should contain the "Account" Object fields on the downloaded Folder Name.
  • From "Object Manager" select “Opportunity” Object.

  • In the “Fields & Relationships” click on the “New” button.

  • Select Formula and then Next.

  • Add a Field Label and Field Name, Select Formula Return Type as “Text” and then Next

 

  • One by one add field names from the “Insert Field” button as shown below.

  • You can add multiple fields as per your choice and then click on Next, Next, and Save.

  • Now the Formula Field is ready, Take this formula field API name.


 


Step 2 - Add Formula Field API Name on Excluded Object 

Now, the Account Field name will appear in the file whenever you download a file from the Opportunity object.