If the font is installed as per your Operating System requires, then the font(s) is available for all your documents (anything on your computer that one can select fonts in).
In Windows, right-click and choose Install. Mac, I think, one just double-clicks on a font <--but it has been a while since I used a Mac.
Is this a font that works in one particular document and not others? Did you create the file where it works?
InDesign has a feature call Document Installed Fonts that allows the sharing of fonts for a particular document so they can be edited or output on another system without needing to install the fonts, but it would be a license violation for you to install any of these document specific fonts unless you also have obtained a license for them.