In this blog, we are sharing the answers to four of the most commonly asked questions the PA Business OneStop Shop receives about business registration. To form an LLC, a Certificate of Organization is required to be filed with the Corporation Bureau of the.Tax Forms, Work From Home - Local Services Tax and Payroll Expense Tax Information(PDF, 245KB), Important Information for City of Pittsburgh Taxpayers. Domestic corporations use this form to: Report their income, gains, losses, deductions, credits. Figure their income tax liability. Corporations must file a state franchise tax report and pay franchise tax for each calendar year the corporation exists. A C corporation is the standard form of incorporation under IRS rules. Request or download Federal tax forms and instructions from irs.gov. To file your taxes with the IRS as a C-corp, you'll need to submit Form 1120.