The difference between Rand, Randi and RANDN?

1,rand generates a uniformly distributed pseudo-random number. Spread between (0~1)
   Main syntax: rand (M,N) generates a pseudo-random number of uniformly distributed m row n columns
Rand (M,n, ' double ') generates a pseudo-random number with a uniform distribution of the specified precision, and the parameters can be
Is ' single '
           RAND (RANDSTREAM,M,N) uses the specified Randstream (which I understand as random seeds) to generate pseudo-
Random number

2,randn generating a pseudo-random number for a standard normal distribution (mean 0 with variance of 1)
     Main syntax: the same as above

3, Randi generation of uniformly distributed pseudo-random integers
     Main syntax: Randi (IMAX) generates uniformly distributed pseudo-random integers in the open interval (0,imax)
              Randi (imax,m,n) generates an MXN-type random matrix in the open interval (0,imax)
              r = Randi ([imin,imax],m,n) generates an MXN-type random matrix in the open interval (Imin,imax)

The difference between Rand, Randi and RANDN?