How do I change the company name that's displayed on the top of the page of a fax??? It's a Canon Faxphone B740.

The following was taken from the User Manual for your machine; go through the whole procedure until you get to Step 8 to change company name. Best of luck and hope this helped!
Greg

Registering Sender Information
Follow this procedure to set the current date and time, register the fax/telephone
number for your unit, and register your name or company name:
1 Press Function
2 Press 01
3 Press SET three times.
• The date and time currently set for the unit
are displayed.

4 Use the numeric buttons to enter the correct
month, day, year, and time.
• Use the month/day/year format. Use the 24-hour
format for the time (e.g. 1:00 p.m. as 13:00), and
enter only the last two digits of the year.
• If you make a mistake, press Clear and enter
the date and time again.
5 Press SET twice.

6 Use the numeric buttons to enter your fax/

telephone number (max. 20 digits,
including spaces).
• To enter a space, press Space.
• To enter a plus sign (+) before the number, press +.
• If you make a mistake, press Clear and start again.
7 Press SET twice.

8 Use the numeric buttons to enter your name
or company name (max. 24 characters,
including spaces).
• If you are unsure how to enter characters, see p. 3-2.
• If you make a mistake, press Clear and start again.
9 Press SET
10 Press STOP to return to standby mode

On the right hand key pad
1). Press Function
2). Press 01 (data registration
3). Press set twice
Display the tel number, change if that is wrong
4). Press set twice again
Enter the company name (unit name)
Use the numeric keys-max 24 characters

if you have otehr problem, please to to the following link and download the users manual.
http://www.usa.canon.com/cpr/pdf/Manuals/B740CanonUserManual3-13.pdf