OP wrote:
"I have a installer packet on my new Mac from the old one. But don't know which version its for. its....
microsoft_office_16.42.20101102_installer.pk
Can I not use this to instal word and excel?"
You HAVE MS Office 2016 already?
Why haven't you TRIED it, to see if it works?
Do so, and get back to us.
I recall reading that earlier releases of MS Office 2016 were not "64 bits" which the later versions of the OS requires.
However, there's an updater available. See this page:
Discusses the conversion of Office 2016 for Mac to 64-bit in the August 2016 release.
learn.microsoft.com
If the newer iMac has an internal SSD, THAT'S what you should be using as a boot drive.
Thoughts for the future:
You can't keep using the same old Macs forever.
The older one is a 2012, right? That's 11 years old already, going on 12.
Even the "newer" one is a 2014, right? That's almost 10 years old.
At some point these are going to fail on you.
You need to start thinking about the future.
I'd suggest a used 2018 Mini as a starting point.
Or perhaps a used 2020 iMac 27".