You don't. Income earned from working or performing a service is always reported on a person's own tax return in their own name, even if they are someone else's dependent.
The only time you would report a dependent's income on your own tax return is if the only source of income is unearned (that is to say, investments and other passive income from investments placed in a child's name) below a certain dollar amount.
Note that in Turbotax online, each account can only file one tax return for one person. You will need to make a separate account for a second return. And the second account will charge separate fees, unless you qualify for free filing. If the income from business is less than $36,000, you will want to use the IRS FreeFile edition of Turbotax, since it includes the self-employment forms that regular Turbotax will charge extra for.
What type of company? it matters. A sole proprietorship? single member LLC? Multi-member LLC? S-Corp? C-Corp? Something else? This matters for correct reporting.
Everything is in my name
Define "everything" please. I assume you (not your son) paid for it and that you (not your son) signed any and all documents having anything to do with the purchase. Did this purchase involved a loan to purchase it? Did you pay for physical assets? Inventory? Good will?
Basically, if everything is in your name, your son purchased nothing. You did - at least when it comes to tax reporting.
Perhaps your son was under the age of 18 at the time of purchase in 2019? (That would explain why everything is in your name)