Firenze Museum Pass?

I think you may be talking about the Firenzecard:
https://www.firenzecard.it/en/faqs

Be aware that even with the card you're required to booking timed-entry reservations at Uffizi Galleries, Accademia Gallery, Palazzo Vecchio Museum, Brancacci Chapel, Tower of Palazzo Vecchio (Arnolfo Tower.).

I strongly recommend that you read through all the details - especially the FAQ section - before purchasing the card:
https://www.firenzecard.it/en/homepage-eng

Based on a previous post, you're going to be based in Florence for 2 months this spring? You may already be there? There is a card you should consider, although it only covers a few (but very good) museums: the Passepartout family card.

https://www.uffizi.it/en/pages/annual-subscriptions (reference the PASSEPARTOUT FAMILY)

This pass is good for 1 year and covers free, unlimited priority entrance (no reservation needed) to the Uffizi, all museums of the Palazzo Pitti complex (Palatina Gallery, Silver and Porcelain Museums, Modern Art Gallery, Costume Gallery, Carriage Museum) and Boboli and Bardini Gardens. If there are two of you, purchase the € 120 family pass: less expensive than buying a € 80 pass for each of you. With the amount of time you'll be staying in Florence, I've no doubt that you'll be able to make good on the purchase unless you're REALLY not a fan of art museums. Without the pass, an adult ticket to the Uffizi is €25 so just 3 visits would cost the 2 you € 150, and that's without seeing the other museums the pass covers.

I believe entry to the museums covered by the card may be limited to once daily but you have a LOT of days to work with! Yep, if you're planning to visit the museums this card covers multiple times, I'd definitely buy this one. It is nominative, and they'll check against your IDs so have your passports with you.

For the rest of the museums, there are some combo passes that might be useful, such as the PASS 72H ACCADEMIA - BARGELLO MUSEUMS pass, although they still require advance reservations to some of the museums they cover, such as the Accademia.
https://www.b-ticket.com/b-ticket/firenzemusei/default_eng.aspx.html

For the duomo complex (not covered by any of the other passes), you can purchase one of the 3 different passes which are good for a single entry to each part of the complex they cover:
https://tickets.duomo.firenze.it/en/store#/en/buy?skugroup_id=3006
Timed-entry reservations are mandatory for the dome climb (covered by the Brunelleschi Pass).

(Edited from original post)

A followup to the above:
The Uffizi website states that....

"At the moment, the Passepartout Family pass can only be purchased through the call centre (toll-free number: 800 615 615 | From abroad and mobile phones: +39 055 0354135) or at our ticket offices."

I don't know if this is a temporary situation or not but, well, if you are already in Florence, it would be easy to purchase it at the ticket office.