This question already has answers here: How can I tell whether my Firefox is 32 bit or 64 bit? (4 answers) Closed 4 years ago .

Firefox 43 comes with a 64bit version. But the one delivered with Ubuntu is 32bit.

Download Firefox link

but in this link there is an option to download 64bit version but its in tar.gz format. Does that mean firefox gets automatically updated and its resources gets added to the software sources or do I have to download again when a new version comes?