Ready stock sales under gst

A registered person supplying taxable goods shall, before or at the time of, - 
(a) removal of goods for supply to the recipient, where the supply involves movement of goods; or 
(b) delivery of goods or making available thereof to the recipient, in any other case, 
issue a tax invoice showing the descripttion, quantity and value of goods, the tax charged thereon and such other particulars as may be prescribed

As per the Tax Invoice rules under GST, if you are selling goods or services to any unregistered person, you have an option to issue invoice in any format other than the format specified. So you may sell goods to unregistered persons as stated in your query normally.