Parents must ensure that their school-age children receive full-time education suitable to their age, ability and any special educational needs they may have.
For a medical appointment: You will need to ask the school’s permission and provide evidence of the appointment, e.g. an appointment card or letter. In general you are asked to make medical appointments outside school time, or if this is impossible, to schedule them as early or as late as possible in the day to keep your child’s time away from school to a minimum.
For a family holiday: Parents do not have an automatic right to take their children out of school for a family holiday. It is entirely at the discretion of the head teacher. See guidance:Attendance and taking a family holiday in term time