contracted GCSE exam marker received fees after tax deducted

Yun2021

Dear fellow members,
I got a new client, who has a full time job and now got a contract as GCSE exam marker. AQA paid her fee after deduct 20% tax and ask her to register as self-employed, which she did. My question is whether she is eligible for £1000.00 trading allowance as freelance GCSE exam marker. and how she should input the fee received (gross or net of tax deducted?)

I did research on HMRC website,it only says the tax have to be deducted, NI can be paid by taxpayer herself. input the information in additional page. But there is nothing saying about trading allowance.

many thanks in advance.
Yun