What are cookies?
A cookie is a small text file that a website saves on your computer or mobile device when you visit the site. It enables the website to remember your actions and preferences (such as login, language, font size and other display preferences) over a period of time, so you don't have to keep re-entering them whenever you come back to the site or browse from one page to another.
As stated in our Privacy & Security [SECTION 7 - COOKIES]
Here is a list of cookies that we use. We’ve listed them here so you that you can choose if you want to opt-out of cookies or not.
_session_id, unique token, sessional, Allows Shopify to store information about your session (referrer, landing page, etc).
_shopify_visit, no data held, Persistent for 30 minutes from the last visit, Used by our website provider’s internal stats tracker to record the number of visits
_shopify_uniq, no data held, expires midnight (relative to the visitor) of the next day, Counts the number of visits to a store by a single customer.
cart, unique token, persistent for 2 weeks, Stores information about the contents of your cart.
_secure_session_id, unique token, sessional
storefront_digest, unique token, indefinite If the shop has a password, this is used to determine if the current visitor has access.
PREF, persistent for a very short period, Set by Google and tracks who visits the store and from where