This is a rail forum, so you'd expect us to recommend rail!

Those are easy trips by train. Pretty short, except perhaps Paris to Florence which might take the better part of a day day. Are you considering a stop in Switzerland ?

We are not stopping in Switzerland 

what pass would I purchase to travel by?

can I travel locally within Paris, Florence and Rome via bus or train?

thank you

I would start here, by looking at how the Eurail pass works. Then you can decide if it makes sense for you.

https://www.seat61.com/how-to-use-a-eurail-pass.htm

If those are your only trips, then it's likely to be cheaper to buy tickets instead.

Three pass isn't valid on local transport, but it's cheap enough in those cities.

This is so confusing And I don’t want to purchase the wrong tickets.

so each destination I would purchase separate tickets vs euro pass?  What site would I check to buy individual tickets?

thank you

Is there one website to plan our trip

Frankfurt - Paris: Cheap Train Tickets | Timetables for Germany & Europe - Deutsche Bahn

Paris - Firenze: Train tickets - Book cheap train tickets - SNCF Connect (sncf-connect.com)

Paris - Firenze - Roma: EN - Trenitalia

Above are the original railway companies.

You may also try for all journeys: Train tickets in Europe - Search & Book on Rail Europe (reseller).

BTW: Most tickets for Italy are just available up to dates before June 9th yet (so you still have to wait, but you may get an idea of timetables and prices if you do check a date just before June 9th).

Thanks-so that’s why when I tried to check times from Paris to Florence it shows no routes?

so starting June 9 it’s available?

thanks for helping 

Correct, you may try an earlier date to get an idea what the connections look like. It will become available for your dates, too and will look very similar.

It will become available much earlier than this but there is no concrete date announced yet.

For Frankfurt to Paris there is a concrete date: Possible to book tickets from March 10th for your date in July (direct high speed train).

BTW: The links above are for buying normal tickets, not reservations (except the last one) - because you did open a second thread where it's written that you already did book your trip (I just wonder because this is not possible for your given date yet?). Or did you buy a railpass? Or did you just book hotels?

We did purchase Global rail pass 

Then I'd recommend to use just Train tickets in Europe - Search & Book on Rail Europe. You may select your pass (1st or 2nd class) and it will show the reservation prices.

For your trips, all high speed trains do need a reservation (they come with a fee, e.g. 18 € for Frankfurt to Paris).