Send email using O365 in an Azure Function C#

Create an Azure Function and the basics for send an email are below:

MailMessage msg = new MailMessage();
msg.To.Add(new MailAddress("someone@somedomain.com", "SomeOne"));
msg.From = new MailAddress("you@radimaging.co.uk", "Paul Beck");
msg.Body = "This is a test message using <b>O365</b> Exchange online";
msg.Subject = "Test Mail";
msg.IsBodyHtml = true;
SmtpClient client = new SmtpClient();
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("your user name", "your password");  // Generate a key so pswd does not change or if account uses MFA
client.Port = 587; 
client.Host = "smtp.office365.com";
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.EnableSsl = true;

Tip:  Azure SendGrid is a great service for sending out emails.  Amazon have SES (Simple Email Service).