Your linguistics professor uses different romaji than your literature professor. Neither is wrong. But you do need to be aware of the different systems so that you don't mix them and use them at the appropriate times.
The Library catalogs and databases use modified Hepburn. An example of this is chizu. Linguists tend to use kunrei-shiki, which is a direct correlation of kana, so 地図 is tidu.
To type diacritics (macrons etc.) in Microsoft Word:
Click on the Insert tab.
Click on Insert symbol, more symbols
Scroll down until you find the character that you want - like o with a line over it.
Then you can create a short cut so that you don't have to do all of this again.
Click on Shortcut key and assign a shortcut (like alt o).
Now when you want to type o with a macron, you can simply use alt o
