SendMail[

  "To" -> "bobexample@wolfram.com",

  "Subject" -> "Mathematica 3D Graphics",

  "Body" -> {

    "Hi Bob,",

    Plot3D[Sin[x y], {x, 0, 3}, {y, 0, 3}],

    "I generated this 3D graphic in Mathematica."

    }

  ];