As a service provider, you should raise GST invoice in RCM method. Add freelancer as your vendor, then deduct TDS on 10% professional service, 2% on technical service.
Whenever, you received service from unregistered person, you won't get tax invoice so, you raise invoice yourself with reference no. If you are using any accounting software enable RCM for this unregistered technical service @ 18%, the software automatically calculate your GST amount.
You should deduct TDS on taxable value of your freelancer amount. For Instance GST invoice, your freelancer bill Rs.30,000/- *18% RCM Rs.5400/- = Rs.35,400/- you GST Tax Invoice.
You should deducted TDS on Rs.30,000/- *2% Rs.600 = Balance Rs.29,400/- you should make payment to your freelancer.