You can report a change of address for other people in your household who are moving with you at the same time as you report your own change of address. The general rule is that you report the change of address for the whole family/household on the same form. You can do this either online or via a paper form which you send to the tax office.
N.B.! For people under 18 years of age, the person or people with parental responsibility who the child is registered as living with is/are obliged to report the change of address and sign the form. If the parents have joint custody and there is an agreement on shared residency, both parents must sign the form. This cannot be done online.