To upload attachments  Using Advanced Search (SOQL) option, follow the below steps:

  1. Go to the Mass File Upload app
    • Open the Mass File Upload app from the app launcher.
  2. Navigate to the Mass File Upload tab
    • Click on the Mass File Upload tab.
  3. Select the Records subtab
    • Within the Mass File Upload tab, go to the Records subtab.
  4. Adjust Record Selection mode
    • Toggle the ON/OFF switch according to your needs:
      • Toggle ON: Select records first and then upload files against them.
      • Toggle OFF: Upload files first and then select records for them.
  5. Select File/Attachment
    • From the "Select File/Attachment" dropdown, choose the Attachment.
  6. Select Object
    • From the "Select Object" dropdown, choose the relevant object.
  7. Choose Search Mode
    • In the search mode, select "Advanced Search(SOQL)".
  8. Add and Run the query
    • In SOQL box enter your query and Click on "Run Query" button. 
  9. Upload Files
    • Click on the "Upload Files" button.
    • Select the files you wish to attach.
    • Confirmation
      • Once the files are successfully attached, you will receive a success message in the table, confirming the attachment created successfully.