Import Notes and Attachments using Data Loader

To import Notes and Attachments into Salesforce using Data Loader, prepare separate CSV import files for each object type. Notes use the Note object (or ContentNote if Enhanced Notes is enabled). Attachments use the Attachment object. Set the Data Loader batch size to 1 for attachment imports.

Importing Notes (Note Object)

Prepare the import CSV file with the following columns:

• Body: Contains all the text information for the note.
• IsPrivate: Set to True to make it a private note.
• OwnerId: The record owner's Salesforce ID.
• ParentId: The ID of the object associated with the note.
• Title: The title of the note.

Importing Enhanced Notes (ContentNote Object)

If your organization has Enhanced Notes enabled (Setup | Customize | Notes | Notes Settings | Enable Notes), insert note records into the ContentNote object instead of the Note object.

Importing Attachments (Attachment Object)

Prepare the import CSV file with the following columns:

• ParentId: The ID of the object associated with the attachment.
• Name: The name of the attachment file.
• Body: The absolute path to the attachment file's location on your local drive.

Inserting Records via Data Loader

1. Open Data Loader and set the batch size to 1.
2. Click Insert. Log in using your Salesforce credentials plus your security token.
3. Select Show all Salesforce objects, then choose either Note, ContentNote, or Attachment depending on the type of record you are importing.
4. Locate the object from the list and browse for your CSV file. Auto-map or manually map the columns to the fields.
5. Click Browse to specify a directory for the success and error log files.
6. Click Finish, then click Yes on the prompt. Click OK.

See also:
Add IDs of available records to your import file
Unable to change the ParentId field for attachments with Data Loader 
Error 'Maximum size of request reached' when you import Attachment or Content

Salesforce Support Video: 

How to Import Attachments in Your Org via Data Loader
How to Prepare Your CSV File to Import Notes