Q: After registration, do I need to apply for additional tax numbers if I need GST or HST? Are there any other numbers I need to apply for?

Yes, additional applications are required.
 For both federal and provincial companies, Canadian companies are generally required to apply for tax registration after incorporation, including Business Number, Sales Tax Number (GST/HST or PST), Import/Export Number if import/export is involved, and if you need to If you need to pay wages to your employees, you need to get a Payroll Deduction.