In simple words, you should perform data field mappings so that the data values in your CSV file are imported into the exact fields in your business app database. For instance, if you use CSV Loader to import your contacts' emails, you map the column in your CSV that contains email addresses to the email field in your business app. Please keep in mind that before configuring mapping, you should check how specific fields are named in your app, as some vendors can be creative with this.
There are three types of fields:
standard fields,
custom fields and
lookup fields. There are also some specifics in the mapping of
fields with date and time values.
Please note that the names of the columns in your CSV file should not be identical to the names or corresponding fields. All you need to know is which data values are saved in which columns. You will be able to select corresponding data field from the CSV Loader list. There will be no need for you to type anything.