What if someone tried to send Crypto to my address?

Assuming I'm a holder of cryptocurrencies, one might inquire: "Could you elaborate on the implications of someone attempting to send cryptocurrency to my address? Firstly, is it possible for someone to send coins to my address without my explicit permission? If so, what measures should I take to ensure the funds' legitimacy? Are there any security risks involved in receiving unexpected crypto transfers? Additionally, how do I verify the source of the funds and ensure they are not derived from illicit activities? Lastly, how do I properly acknowledge and process such transfers, if they are indeed legitimate?