Time to time, you may need to personalize the email content different based on your recipient attributes. In this case, you will need to use the “Conditional Personalization Tag” in your email content:
[IF:condition1<>condition2] true content block [ELSE] false content block [ENDIF]
The expression part can contain static or dynamic elements. For example, if you want to greet your recipient personally IF the recipient has FIRST_NAME global custom field value, you can use;
[IF:%Subscriber:FIRST_NAME%=]Hi there,[ELSE]Hi %Subscriber:FIRST_NAME%[ENDIF]