If you’d like to migrate Notes with HTML tags, then you need to enable Notes in Salesforce. Follow the directions here.
If Notes are disabled or not available in your Salesforce platform, then the Self-Service Tool will migrate Notes by default into Notes & Attachments object in SF.
Note: Both Notes & Attachments and Notes can still be invisible in the CRM layout even after enabling them. To add Notes to your layouts, you can click on Setup, open the Object Manager and select the Object you'll be using. Select Page Layouts from the left panel Click on the Related Lists section and drag the Notes & Attachments Related List into the Page Layout if it is not already there.