The number of people in each row or column cannot be less than 3, so when 48 is decomposed into two multiplied numbers, these two numbers cannot be less than 3.

48=3* 16=4* 12=6*8

So in the rectangular formation, there are the following schemes:

There are 3 people in each row, in row 16.

4 people in each row, 12 rows.

Six people in each row, eight rows.

Should I write down the following?

3 rows per row 16 people.

4 rows per row 12 people.

Eight people in each row, six rows.

It's up to you.