You can insert equation symbols outside a math region by using Math AutoCorrect. You can also create math equations using on the keyboard using a combination of keywords and math autocorrect codes. New to Word for Office 365 subscribers is the ability to type math using the LaTeX.
If you are running Office 365 version 1707 or later, the Equation Editor allows you to convert LaTex into the native format. See the first part of this answer. In older.
For a while now it's been possible to switch Word's math input mode from UnicodeMath to LaTeX. We didn't advertise this highly requested.