If you practice business as a private trader the income of your company is your personal income. Then again, you bear the responsibility the business alone, with your personal assets. The profits of your business are taxed as earned income or capital income alongside your other income.
Starting and managing a company as a private trader is relatively easy. For bookkeeping, you only need to sum up your expenses and income and save the receipts (this is known as single-entry bookkeeping). As a private trader, you are not obliged to make an annual audit of the accounts or a performance audit.
As a private trader, you always start the company alone – you are the company. Private trader is the easiest and the most risk-free form of entrepreneurship: you have relatively few legal obligations, and the tax authority has published good instructions on submitting a business tax return. The essential thing to understand about being a private trader is that you answer for all your agreements, commitments and debts with your personal assets.
Another essential characteristic is that you only need to trust yourself; you do not need partners.
https://www.prh.fi/en/kaupparekisteri/yrityksen_perustaminen/privatetrader.html
https://www.suomi.fi/company/starting-a-business/forms-of-enterprise/guide/private-entrepreneurs