If one receives a package through US mail or fedex, and It arrives on yom tov (a book), can one open the parcel?
This will generally be permitted.
The package must be opened in a way that is “destructive” (such that it cannot be reused), so that there should be no concern for the prohibition of tearing. Some are careful to refrain from opening envelopes at all on Shabbos and Yom Tov (see Mishna Berurah 307:56 and 340:41; Shemiraa Shabbos KeHilchasah 28:6 and footnotes) and this might apply to the package.
Please see here concerning the matter of something that arrived from outside the techum – a problem that applies to Yom Tov as to Shabbos.