TradFi consist of retail, commercial and investment banks, and FinTechs (tech companies that operate in finance).
For example, Goldman Sachs and JPMorgan Chase as banks, and SoFi, Square, and PayPal as FinTech companies.
They are centralized, regulated by a series of government regulators, and comply with strict Know Your Customer (KYC) and Anti-Money Laundering (AML) regulations.