Final answer:
A sole proprietor must use Form 1040-SE for self-employment taxes, in addition to the standard 1040 tax form for federal income tax filings, and may need to file quarterly estimates using Form 1040-ES.
Step-by-step explanation:
For federal taxes, a sole proprietor is required to use the self-employment tax form 1040-SE. While the 1040 tax form is the standard federal income tax form for individuals, the 1040-SE is specifically designed for self-employed individuals to calculate the tax due on net self-employment earnings.
It's important to note that self-employed individuals may also need to file quarterly estimated taxes using Form 1040-ES if they expect to owe tax of $1,000 or more when their return is filed.