To find if a font is embeddable, right-click on the font and choose Properties. Then choose the Details tab and check the Font Embeddability property. If it is marked as Editable or Installable, then you should be able to embed it. If it is marked Print/Preview, the resulting file will be read-only, as the font only allows the font to be printed or read on-screen, but not edited. If it marked Restricted, then you won't be able to embed it at all.
All modern fonts are OpenType format. This format has 2 flavors: TrueType OpenType, with a .ttf file ending, and PostScript OpenType, with an .otf file ending. Sometimes, you'll run across old fonts that have a .ttf ending and are TrueType, but not in OpenType format. That format is deprecated now.