MathType is a very user-friendly and powerful mathematics formula and equation editor tool for Windows and Macintosh.
It lets you create mathematical notations and equations for word documents, presentations, web pages etc.
I recently used this for my paper that I published in an international journal. I’ve installed this tool on my computer. It integrated with Microsoft Office Word very well. With this tool, creating equations is so much easy in word document.
MathType is a product by Design Science. They have a very good tutorial for beginners. You can use the 30 day trial version. If you intent to often use it then you can buy it. Here is the home page of the product for your reference.