Word – Shortcut of ‘adding an equation’ in Word 2016 for laptop

These are the same format. My company, Design Science, makes the Equation Editor that comes with Microsoft Office on Mac and Windows since 1991 or so. MathType is the fancy version of Equation Editor with lots more features, including the TeX input feature you mention. Your publisher should be encouraged to mention that it accepts both MathType and Equation Editor equations as most publishers do. I suspect they have been getting documents containing MathType equations and handling them just fine all along.

By the way, the next version of MathType will feature compatibility with Mac Office 2011 which is due out later this month. As you may know, Microsoft left out Visual Basic for Applications (VBA) support in Office 2008 but they are bringing it back in this new version. That means MathType will have more commands like it has in Office 2004. In particular, you will be able to insert new equations without going through the Insert Object process.

It's "Alt+=", but it only works in docx files and you should have VB-component installed to enable macros.