You can still send an invoice if you’re not registered for VAT or GST—just delete the tax field on your invoice. If you meet the income threshold for VAT or GST, you should register as soon as you can. However, you can still retroactively extract the VAT or GST from your income if necessary. And keep in mind that putting VAT or GST on your invoice isn’t just for your benefit. It also benefits clients that can claim the taxes back on their return.