I believe you're a little confused. What the "any user" option is referring to is in relation to whomever is assigned as the destination user group. For instance, you can have a role of multiple users and have it set for any user to finish the worklist item. If you want all users to be able to action the item, then I would add Domain Users and then any user on your domain will have access to the worklist item.

Thanks for reply. Exactly, we are planning to create a set of domain user to solve this issue.

But as a beginer I am curious to know about variuos options in K2. After reading the reply I understood that when we select 'Any user' option any one of the destination user we provided can take the action. This is what happening with "Only the destination user" option, only the provided user set can take action (any one of them). I am yet to understand the difference clearly. Is this anyway related to destination slots?

If don't mind helping freshers please help me in finding the difference between the two options.

Yes, it's related, but the destination slots work a little differently. For example, you have a role created for the destination users that has x number of people. If you choose the option to plan per destination and all at once, it will run as a parrell destination versus once at a time which will require one before the other to be finished. If you create a slot for each destination, then it will require each user in the role to take an action on the worklist item before continuing. If you specify, for example, 1 slot, then it will only require the first action taken by which ever user grabs the worklist item first.