If you were not born in the UK and do not have right to remain/settled status you will need to apply to stay in this country. This also applies to your children. They will also need permission to remain in the UK.
If you arrived in the UK before 30th December 2020 you have until 30th June to make your application.
Please follow the link below for further details or seek advice and support from the immigration service.
https://www.gov.uk/settled-status-eu-citizens-families