We have assembled a collection of useful forms for your convenience. If there are any additional forms that you would like to see, please let us know. You will need Adobe Reader to access the forms listed below. Download Adobe Reader   Payroll: Complete Forms W-4 and CT-W4 so your employer can withhold the correct Federal and state income taxes from your pay. Because your tax situation may change, you may want to refigure your withholding each year. Form W-4 Fill-in Form Form CT-W4 All employees, citizens and noncitizens, hired after November 6, 1986, must complete Section 1 of this form at the time of hire, which is the actual beginning of employment. The employer is responsible for ensuring that Section 1 is timely and properly completed. Form I-9 Fill-in Form  Employer: Form SS-4, Application for Employer Identification Number, is for use by employers, corporations, partnerships, trusts, estates, churches, government agencies, Indian tribal entities, certain individuals, and others. This form is available in both paper and online formats. Form SS-4 Fill-in Form Form SS-4 Online Application Use Form Reg-1, Business Taxes Registration Application, to obtain a Connecticut tax registration number or to register for additional tax types under a previously obtained Connecticut tax registration. This form is available in both paper and online formats. Form Reg-1 Fill-in Form Form Reg-1 Online Registration Use Form W-9 to request the taxpayer identification number (TIN) of a U.S. Citizen (including a resident alien) and to request certain certifications and claims for exemption. Form W-9 Fill-in Form Form OS-114, Sales and Use Tax Return, must be filed even if no tax is due or no sales were made. Form OS-114 Sales and Use Tax Return   Individuals: Use Forms 1040-ES and CT1040-ES to figure and pay your estimated taxes. Form 1040-ES Fill-in Form Form CT-1040ES Use Form 4868 and Form CT-1040 EXT to apply for an extension of time to file an individual income tax return. Form 4868 Fill-in Form Form CT-1040 EXT Use Form 4506-T to request a copy or a transcript of a tax form. Form 4506-T Fill-in Form   Partnerships: Use Form 7004 and CT-1065/CT-1120SI EXT to apply for an extension of time to file a partnership income tax return. Form 7004 Fill-in Form Form CT-1065/CT-1120SI EXT    Corporations: Use Form 7004 and Form CT-1120 EXT to apply for an extension of time to file a corporation income tax return. Form 7004 Fill-in Form Form CT-1120 EXT   S Corporations: Use Form 7004 and Form CT-1065/CT-1120SI EXT to apply for an extension of time to file an S corporation income tax return. Form 7004 Fill-in Form Form CT-1065/CT-1120SI EXT