I am new to marketo , just wanted to know key difference between these two points(group list and group smart list).
Thanks in advance.
Welcome to Marketo Ashish,
Group Lists are static lists and Group Smart Lists are dynamic. You can read a bit more about them here: Smart Lists and Lists - Marketo Docs - Product Docs.
Think of a group list as a group of leads from a list upload or event attendee list. Think of a smart list as a group of leads that meet a certain criteria (ex. have a score above 10; so it is always changing as it picks up and drops off leads that qualify).
A smart list is dynamic in that it will be updated in real time every time it is called. It is in fact a set of filters that run against the database and get the latest and greatest audience in real time.
A Group List is what you would traditionally refer to as a list. It is static in nature in that you update the list at a point in time and the list stays the same until you explicitly change it by adding or deleting names from it