I heard that soprano uses their head voice more often than chest voice. But just like a tenor, they all have two passaggios. For example, I have found that a coloratura soprano would have her passaggios at G#4&G#5 comparing to the male counterpart leggiero tenor at D#4&G#4. The zone in between is the meant to be sung via mixed voice. Also, the range for a coloratura soprano is C4-F6 comparing to C3-F5 of leggiero tenor. So basically the pure head voice range of both voice is equal. So how can you say the soprano sings mostly in head voice? Note that soprano would also have to sing in zona di passaggio and below primo passaggio as well (There is a link below of a lyric soprano singing from G4-A5). The only different I can see is that soprano has a relatively lower primo passaggio than male singers (Due to the lightening of the voice). Is this what they mean? To have a headier mix voice? A lyric soprano singing in the range G4-A5, most of the notes fall below the second passaggio
Depends on the vocalist, really.
That said, in the musical theater world, sopranos typically try to use chest voice up to somewhere between C5-G5 (as I said, it varies by vocalist) before switching to head voice. For soprano voices, it is usually much more comfortable / sustainable for them to use their head voice, and most prefer to use that whenever they can. The same cannot be said for the other voice types (exceptions notwithstanding).
Whenever discussing ranges for vocalist it is important to discuss them in terms of what is "most common" as opposed to hard lines.
It really varies from one soprano to another. For example, if you youtube Karen Kelley "I call him Lord", you'll hear here switch from head to chest when she starts to sing "But I all him Lord", prior to that she's singing head voice. Just one warning if you do listen to that video, she'll hit an "F#" 2 octave over middle "C", and it's pretty loud, so be careful!