For any employee, you must report their wages on form 941 and issue them a W-2. For your own minor child, you don't have to collect social security and medicare tax.
However, you also need to look at state laws and regulations. You may be required to pay minimum wage (although there may be an exception for employing your own child). You may be required to issue a pay stub that conforms to certain regulations (for example, in NY, a pay stub must be issued and must contain about 15 mandatory items, violations are $100 per non-conforming pay stub).
There may be hours of work limitations for minors based on their age and school attendance, and you may be required to get a work permit for your child signed by the school. If the job involves working with hazards (including cleaning chemicals that might be considered hazardous) there might be further regulatory blocks until the employee turns 18. You may be required to offer and pay for certain benefits (family medical leave, for example) although once again, there may be exceptions too any or all of these regulations for your own minor children.
In short, don't just consider federal tax law. Also pay attention to state tax requirements and state employee requirements.
