If you are planning on uploading a subscriber segment with a comma-separated value (CSV) file, use thest guidelines to format a CSV file before uploading it.
Add Column Header
The first row of the CSV file should contain headers for each column. If you don't currently have headers, you'll have the option to create your own headers during the formatting process.
The order of the columns must be formatted in the below order, left to right:
1st column with 'phone' in the header for the phone number
2nd column with 'firstname' in the header for the first name
3rd column with 'lastname' in the header for the last name
4th column with 'email' in the header for the email address
5th column with 'birthday' in the header for the subscriber's date of birth
6th column with 'custom' in the header for any customized data
Even if you do not have data for all columns, you need to include the column headers in the CSV file you want to upload. When you upload your file, the header is used to match that column with an existing field. It uses the header to find any fields with the same name.
The rows in the file will be matched with existing subscribers in that group. It will not create duplicate subscribers.
Ensure that your CSV file contains columns with all headers outlined above.
Header title should be lowercase
Each subscriber should be on a new line
Review your data to make sure that the formatting is correct before uploading the file. This will ensure you have a high match rate.