For us dispatchers in the office, it's a piece of scrap paper. Some people have made forms with blanks to fill in. I used to just abbreviate everything on a piece of scrap paper and then enter it into the incident history.
Example:
Box 1563
5 FL
20 Br OMD
100X50
St
Yd
Yd
Yd
2 l/s, 1 l/o
TOU
PRI-
Sec srch I/P
DBTFL
Translation: Box 1563 the fire is on the 5th floor of a 20 story Brick Occupied Multiple Dwelling. Expoure 1 is a Street, 2 through 4 are yards, 2 lines stretched, one line in operation. Trucks opening up, Primary Search is negative, Secondary Search is in progress, Fire is Doubtful. Most of the abbreviations you see here are used by dispatchers in the offices today.