latexmicrosoft-office
There is no restriction on platform in the answers, but a few things to keep in mind:
If you came across this, here's answer at tex stackexchange (via Juan A Navarro):
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 versions of Office, the Equation Editor can understand certain LaTeX components. However, it builds the equation as you go, and you cannot convert an entire LaTeX equation. See the second part of this answer if you are running:
Put the Equation Editor into LaTeX mode. In the Equation Editor Design ribbon, go to the Conversions group and click LaTeX.
Type the LaTeX.
Open the Convert dropdown menu and click Current - Professional.
The LaTeX will be processed into the Equation Editor's native format.
You can also convert back to LaTeX to edit the equation.
You have to use the dropdown menu because the Convert button doesn't toggle automatically between Linear and Professional. It keeps the last-used command.
There are some limitations. For example, the Office 365 Equation Editor does not understand the \begin and \end commands. See the Microsoft documentation for examples and possible workarounds:
Very few people realize that the built-in equation editor in Word 2007 actually understands LaTeX-style equation entry. Simply insert a new equation, and then type LaTeX into it. As you type, Word will build up a graphical representation of the equation.
Once it appears in the GUI, you can no longer edit it as LaTeX. Word does not have an embedded TeX processor -- it's just doing pattern matching to convert simple LaTeX syntax into the native equation format. You should therefore not expect to get perfect fidelity for super-complex LaTeX equations. However, it's enough for probably anyone but a mathematician, and it's a lot faster than clicking elements with the mouse.
The Word 2007 equation editor also has a linear equation entry format, which is fairly intuitive and does not require familiarity with LaTeX. For example, typing in (a+b)/(c+d) will result in a nicely-formatted fraction.
Notes:
Many scientific journals will not accept Word documents with the new equation format -- even if you save as .doc instead of .docx.
This doesn't turn Word into LaTeX. It just does the equations themselves, and nothing else. You don't even get equation numbering.
Best Answer
I love using the built-in Equation Editor in Word 2007. Alt + = brings up the editor, then you type this:
This will produce the following:
It doesn't get much easier than that.
There is also an entire paper (PDF) about using plaintext to type up formulas.