My son started a single member LLC in January 2024 for an online retail store and has made zero dollars to date. Does he need to send anything quarterly to report to the federal government or just report at the end of the year on his personal taxes? I ask because I do not want him to incur penalties for not reported quarterly even though he has not made any profit.
He has been reporting monthly to the Oklahoma Tax Commission.
There are no quarterly "reports" to send to the IRS for your son's business. If he starts making some income, he can pay estimated quarterly payments to the IRS---but it sounds like there is no need for that yet.
https://ttlc.intuit.com/questions/1901110-do-i-need-to-make-estimated-tax-payments-to-the-irs
Since he has no income yet to report for his self-employment there is no need for him to send any estimated tax payments to the IRS.
Self-employment taxes are only required to be paid if the business has a net income after expenses.