How Can I assign Edit permission on Tasks list to AssignedTo users only. Any other user can view the Tasks but can not edit/delete the task. Only AssignedTo users can edit that task.
You'd need to manually change the permissions of said item, or e.g., implement custom Event Receiver that will modify the permissions when the item is created.
You can use the designer workflow to user/ group from list and provide item level permission to Only AssignedTo user.
Log Remove User from list to the workflow history list then Remove these permissions from item in this list then Add these permissions to item in this list
Add these into Impersonation Step available in designer