I want to know that what is the main difference between goal and profile(Persona)?
A goal in Sitecore is any action that a user completed. It can be a page that has been viewed, a form that has been completed or other actions. Goal facets can be used to describe different aspects of a goal that you might want to track. These could be categories for your goals or descriptions that you can apply to multiple goals in order to better organize them. You can use goal facets to create and implement personalization rules that show content to your contacts based on the type of goal that they have triggered.
So for example, if someone downloads a brochure and there is a goal associated to that action, it will show the form after it, which can be achieved by goal-based personalization.
On the other hand, Profiles are the way to identify your visitor’s behavior and their content interests. Lets use a simple example to demonstrate:
We have a website of a college and we want to understand the visitor behavior to know if a visitor is a fresher student or a graduate student or a parent visiting for his/her children. The behavior can understand by identifying the visitor's behavior and can achieve by profiles and if content author want to personalize the content based on the visitor this will be persona-based personalization.
In simple behavior vs action = persona vs goal.