Pdf/A and xml based formats in theory. And in general use open source software. In practice use the Odf format because I support that and it does what you want

Pdf/A and xml based formats in theory. And in general use open source software. In practice use the Odf format because I support that and it does what you want. And don't use pdf/A because too many implementations are pretending they produce pdf/A while they don't.