Welcome to the world of Ecommerce! Happy to have you starting your business with us. ?
Although many of these questions will be best answered by a tax professional in your area, I can definitely give you some tips and insight from experience.
Registering a business is not required by Shopify. However, the country you are in may need you to register your business. In Canada, and some other countries, you can go without a business license or tax ID until you hit a certain revenue per year.
I wont be able to advise on what this number is, but that is something to keep in mind! - Although you may not need it now, you may in the future.
Secondly, Shopify will not collect or pay income taxes for you. So when (or if) you are at the point of needing to submit tax information be sure to have set aside the income from tax to pay those taxes. (again may not apply in all cases)
To answer your question, dropshipping is by no means illegal, but do be sure you are following proper tax rules set out by a tax professional, and verify you are selling legal goods. Again, none of this is legal or tax advice, simply tips to point you in the right direction!
Here's also a handy blog post of ours regarding taxes you may find interesting.
Hope this gets you going in th right direction.
Morgan | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog