What is it …

Data Extension is additional data table for subscriber extended attribute information.

How many types …

3 Types: Standard, Filtered, and Random

How do we fill …

• Uploading file from desktop
• Uploading file from FTP folders
• By connecting to database, SQL and Salesforce
• Via API calls
  

When do we use …

• Large volume of subscriber records( > 500K)
• Faster imports
• Data with relationship or flexible subscription
• Sending messages
• Triggered actions based on data
• Using the SOAP API
  

Data extension is very powerful Salesforce Marketing Cloud component to store subscribers data.