Can I buy over the counter on Robinhood?

Could you please clarify for me? When it comes to Robinhood, is it possible to purchase cryptocurrencies or other financial instruments over the counter through their platform? I'm just a bit confused about the options available on Robinhood and whether or not over-the-counter transactions are an option. Could you explain this to me in a bit more detail? I'd really appreciate it if you could provide some clarity on this matter. Thank you in advance for your help!