Set up child self assessment

Hello My daughter age 7 are currently working as model/acting, how can I set up her self assessment please? She will need a UTR and NI as well? Am I allowed to filled her forms on her behalf? Your regards Preeya

Hi Pranpreeya7777,
To register your daughter for Self Assessment, and to confirm on her record that you are authorised to act on her behalf, write to us at:
Pay As You Earn and Self Assessment,
HM Revenue and Customs,
BX9 1AS.
Please confirm your names, dates of birth, and address, that you would to register her for Self Assessment (and why), and also what you would like authority to do on their behalf.
Both you and your child should sign the letter, confirming that they agree to your acting on their behalf as a third party.
Thank you.