I have a brother 4100 fax. how do I change the information on the fax transmission page? thank you

If your date and time are not set yet, press Menu, then 1, then 2 and enter the date and time, pressing Set after each entry. Enter time in 24-hour format so it will display AM or PM properly.

For other info at the top of your fax transmission page after date and time, such as your fax and phone numbers, and company name:
Press Menu, then 1, then 3 for Station ID info.
First put in your fax number and press Set.
Next put in your phone number and press Set.
Next press the buttons for your company name and press Set.
Press Stop/Exit to return to the date and time display.

Here is info on inputting text, from the manual:
Entering Text
When you are setting certain functions, such as the Station ID, you may need to type text into the machine. Most keys on the dial pad have three or four letters rinted above them. The keys for 0, # and don’t have printed letters because they are used for special characters.
By pressing the appropriate number key repeatedly you can access the character you want.
Inserting Spaces
If you want to enter a blank space, press once between numbers and twice between characters.
Making Corrections
If you entered a letter incorrectly and want to change it, press to move the cursor after the last correct letter. Then press Clear; all letters above and to the right of the cursor will be deleted. Re-enter the correct characters. Also, you can back up and type over incorrect letters.
Repeating Letters
If you need to enter a character that is assigned to the same key as the previous character, press to move the cursor to the right.
Special Characters and Symbols
Key - once - twice - three times - four times - five times
2 - A - B - C - 2 - A
3 - D - E - F- 3 - D
4 G H I 4 G
5 J K L 5 J
6 M N O 6 M
7 P Q R S 7
8 T U V 8 T
9 W X Y Z 9
Press for (space) ! “ # $ % & ’ ( ) + , - . /
Press # for : ; < = > ? @ [ ] ^ _
Press 0 for é à è ê î ç ë ö 0