Does having my own business number and invoicing help prove I'm not a personal services business?

Having a business number and issuing invoices are useful administrative signs of running a business, but on their own they don't establish that you're not a personal services business. CRA applies a substance-over-form test, looking past the paperwork to the real nature of the working relationship, who controls how and when the work gets done, who owns the tools, whether there's genuine financial risk, and how integrated you are into the client's operations, rather than simply accepting that invoicing through a registered business number settles the question.

Someone who invoices through a proper business number but is, in every practical respect, treated like an employee, set hours, close supervision, using the client's equipment, no real chance of profit or loss, can still be found to be operating a personal services business despite having all the administrative trappings of a business in place. The formalities matter as part of a broader picture, but they don't override what the actual relationship looks like day to day.

If you want your corporation to hold up as a genuine business rather than an incorporated employment arrangement, the administrative pieces need to be paired with real operational independence, not treated as a substitute for it.