trojan virus

Can apple devices be infected with trojan virus ? I have received an email from an anonymous saying they’ve hacked into one of my devices and uploaded a trojan virus where they had access to my webcam and all my activities on all my devices and have footage of me and are blackmailing me into releasing it and sharing it with my contacts if I don’t make a bitcoin payment.

I am really worried can someone help me ? Can this be true ? How can I check if my device has been hacked a mac book and iphone ?