The UK Government is now open for applications for Settled Status from EU Citizens. At present the system is only available to those who have access to an Android smart phone. It is supposed to become fully operational and available to others at the end of March.
Mrs May announced on 21 January that the fee of £65, previously announced, would not after all be levied when the scheme is fully operational, and will be refunded to those who apply earlier.
For details: https://www.gov.uk/apply-stay-uk-leaves-eu-test-phase