I purchased a Eurail Ticket, and am flying into Milan Airport, and plan to go directly to Venice Lucia. Can the Eurail ticket be used on the Milan Express train to Cardona too? or only on the train from Cardona to Venice?

Also, do I need reservation for both trips?

Oops, I meant Milano Centrale as opposed to Cardona

What do you mean by Eurail ticket? Did you buy a ticket from a reseller (Eurail? Raileurope?)?

Your ticket would not be good for the train to Cadorna unless it lists Malpensa as your starting point with a change at Cadorno to Venice.

Since we don't know what you bought (there is no such thing as a Eurail ticket) it's hard to say. You likely purchased a ticket for a Trenitalia train (Trenitalia is the Italian rail company), but you would need to look at the ticket to see if it's for an AV train, ES train, ESCity train (likely), IC train, or R train (no seat reservations possible on R trains).

Opps! Milan. Still, if your ticket is good to Milan (so far there are only two train departures daily from Malpensa to Milan) it will list Malpensa with a change at Milan Centrale.

All AV, ES, ESCity, ICPlus, IC train tickets come with seat reservations included (this will be on your ticket - class, car #, seat #).

I am guessing she purchased some type of a rail pass as opposed to a specific ticket. Rail passes in Italy generally are not a good value. If she is that confused now, what till she gets there. I know they were working on train service to Centrale. Is that now operational? I assume it puts the shuttle service out of business.

Trenitalia is only showing two trains to Centrale operating so far, one at 12:21 and 19:21 for 12€ (42 minutes). It's an AV train that continues on to Florence so you wouldn't have to change trains from the airport. I think when the winter schedules are posted in the next few weeks there will be more train times listed.

Yup, it looks like the OP bought a rail pass. Since there are a score of these available the OP should read all of the information that came with the pass, especially the small print on the cover envelope.

What is a Eurail Ticket?