It depends on the "editability" of the PDF.
Some PDF creation programs leave data in them for further editing. But this is rare and generally such additional data is compatible with one family of software (e.g. Adobe Illustrator, InDesign etc.)
In addition, text can be written in two ways:
1. As text that is rendered and displayed as curves when displayed. The appropriate typefaces may or may not be embedded in the file. In the latter case, the program displaying the PDF file will use the "closest" typeface it finds in the system.
2. As curves. There is no need to embed typefaces, but data for optional editing can be embedded anyway (this is generally not done when text is saved as curves).
You can use "Foxit PDF Editor" - trial version. There, after clicking on the text, information about its features will appear in the next window.
