Class F1 was introduced by the Business and Planning Act 2020, effective from 1 September 2020. It comprises schools, museums, galleries (not for sale), libraries, halls, places of worship, church halls, law courts, non-residential education and training centres (these are all former Class D1 uses). It should be noted that the former D1 uses of health centres, clinics, nurseries/creches and day centres are now classified as 'Class E' uses and not F1.
Permission is not required to change between uses within Class F1 unless there is an existing restriction on a current permission (i.e. a restrictive condition) or an Article 4 Direction is in force.
The full regulations can be accessed here: https://www.legislation.gov.uk/uksi/2020/757/made