There are four different types of ukulele’s.
Smallest ukulele. Ideal for young beginners. They’re light and easy to hold. Suitable for playing simple chords at the bottom of the neck. Has a higher frequency tone because of its small body
Longer neck and slightly larger body, the concert is ideal for older children and adults. It has a mid-range tone and is perfect for playing both chords and single picked notes.
Again, bigger than the soprano and concerts, the tenor has both wider body and longer and wider neck so people with bigger fingers and taller in stature would be better suited with a tenor. They also have a more resonant sound. To further this mid-range tone you can replace the high G string with a low G which gives your chords a richer tone.
The biggest size, the Baritone has bass tones than the other three, more like a tenor sized guitar. Unlike soprano, concert and tenor which are all tuned to G, C, E, A, the Baritone is tuned to D, G, B, E which are the tunings of the top 4 strings of a guitar. These instruments are useful to flesh out the sound of a ukulele group and give the overall sound a bottom end. It’s important to remember that because the strings are tuned lower than the other ukuleles to get baritone versions of your ukulele songbooks because they contain different chords.