Change to freelancer

Hi, I've been working as an employee for the past 10 years and been paid via PAYE.I've been submitting self assessment tax return as well and now I'm planning to work as a freelancer for a change. My questions are: 1. Is it correct that I don't need to inform HMRC about the change until my next tax return in section SA103? 2. If that's the case, would this affect my qualification on the 30hrs free childcare (given that I'll be earning above the threshold) as HMRC won't receive my NI contributions until the next tax return? Thanks in advance.

Hi,

You will need to register as self employed if you wish to pay voluntary class 2 NIC, even although you are completing a self assessment tax return each year.  
Self assessment is used to collect class 2 and class 4 NIC, where the net profits meet the NIC thresholds.

Rates and allowances: National Insurance contributions

You can register at:

Set up as self-employed (a 'sole trader'): step by step

Thank you.