Upload Option
Here are two kinds of files that can be uploaded
1) A text file with extension .txt
2) A Comma delimited file with extension .csv.

You will learn how to Upload files with these two formats in the below segments.
Uploading a .text file
 
  A .txt file is a simple file created in a text editor (Notepad).The correct format of the contents (email addresses) in that file is important .The file should have email addresses and the first name and last name (if any) separated by a “,” (comma).Each new email address entry should be in next line as shown above
 
  To upload a .txt file go to the Upload option within the LIST menu. You have to first enter a list name. In the Select list text box you need to give the path of the .txt file that you would be uploading. Browse button will help you to find the path. Then click the Upload button. The NewList will get uploaded.
Uploading a .csv file
 
  CSV means Comma Separated Values. A .csv file is created in an excel sheet and is saved as Comma delimited as shown in the above picture. The format of email addresses in that file should be the same as how we created in .txt file.
 
  To upload a .csv file go to the Upload option within the LIST menu. You have to first enter a list name. In the Select list text box you need to give the path of the .csv file that you would be uploading. Browse button will help you find the path. Then click the Upload button. The NewList will get uploaded.