Documented in Volume 1 of the UNIX Programmers Manual.
% pr -h "The Title is goes here..." inputfile
will print-format contents on inputfile. Headers will look like this:
Mar 17 14:40 1983 The Title goes here... Page 1
% pr -8 -w80 -t -l1 infile
will reformat infile into 8 columns, with 80 characters across the
screen, suppressing blank lines and header lines.
The -l1 is a trick. pr can have a hard time with several columns unless
the -l1 is there. (It specifies screen length of one line!)
% pr -m -t filex filex > filexx
will merge (horizontally across lines) the contents of filex with itself
omitting heading line and blank lines, and store the results into filexx.