First i want to see if the email is telling the truth:
I don't think it is possible to go through someone's system with visiting a website or a video, If you have downloaded and ran any file or if your browser is too old then it is possible that the hacker reached to your system and after that anything is possible.
Is there any specific info related to you in the email?
Email,password,Ip/location,Web Browserversion, yourOSyourmonitor modeland ... is considered normal, But getting webcam and recording don't seems real and possible.
Possible actions:
If you think this is a spam email which is sent for a thousand innocent person so Flagging and Reporting and Deleting will make his job harder next time. Because the sender will be blacklisted, His tools will get flagged and suspended and a lot more trouble.
Analyzing email's header can expose some information about the sender, like ip, The tools he is using or ... . Which is a very technical thing.
The hacker can see if you opened and read the email, So better to not opening these email next time.
You have the upper hand here, With 2 Step Verification, Back up email or any possible way you can change your system and email's password.
Finally Ignorance is the best solution, I receive 10's of this every day. Mass spamming is a ordinary thing for a hacker, When millions of emails are out there.