1. From Setup, type data import into the Quick Find box and select Data Import Wizard.
2. Click Launch Wizard.
3. Choose the data that you want to import. In the example below, Accounts and Contacts has been selected from Standard objects.
4. Specify whether you want to add new records to Salesforce, update existing records, or add and update records simultaneously. In the example below, add new records has been selected.
5. Specify matching and other criteria as necessary.
6. Select the CSV file to upload and click Next.
7. Map your data fields to Salesforce data fields and click Next.
8. Review your selections and click Start Import.
9. You'll get a confirmation message that your import has started. You can review the outcome of your import from the Bulk Data Load Jobs page by clicking OK.
For more information about reviewing the success of Bulk Data Jobs in Salesforce, refer to this article: