Deferred revenue is an amount that was received by a company in advance of earning it. The amount unearned (and therefore deferred) as of the date of the financial statements should be reported as a liability. The title of the liability account might be Unearned Revenues or Deferred Revenues.
Calculate MRR and ARR based on revenue periods. Please make sure to include only recurring revenue items, excluding one-time charges and dividents - but including discounts.