A task is something that takes 30 minutes or less to resolve and can generally be handled within the admin panel of your WordPress site. They can be combined for larger, more complex tasks (i.e. two tasks to cover a one hour job).
A subscription is for WordPress Maintenance where we manage your plugins, theme and core updates on a weekly basis to make sure you're site is running smoothly.
If you’re not sure what’s the best option for you, just ask!