Then you copy-paste your mail into your email system like Gmail or Yahoo. If you copy equations from within Word or another Office app and click their thumbnail in the Office Clipboard task pane to paste into the document they will be editable in MathType just like normal MathType equations. If you are using Word 2016 for mac please note following things about MathType I have copied here.
Copy and paste Math Symbols text wherever you want.
Copy and paste Math Symbols text wherever you want. Below is a recommended way to copy from PDF using Snap shot of Adobe R eader. I copy from Mathcad and use the paste special in word as follow. There are a number of good resources on the web available to help you identify the LaTeX symbol for each math equation.