please read this article or i copy some of it here :
Changing the default set of fonts Maple uses in the Standard interface is a two step process.
To change the default font for a type of input or output:
1. Select Format -> Styles
2. Select the style you wish to change and click the "Modify" button.
3. Change the font type, size, colour, etc. as desired and click "OK"
The default input/output modes for Maple are:
2D Math input: "C 2D Math"
1D Math input: "C Maple Input"
2D Math output: "C 2D Output"
The above steps will apply the change for the current worksheet only. If you were to restart Maple, the old default values will be restored. You must make a user defined style set if you want this change permanently. Here is how you can save the changes made above:
1. Select Format -> Manage Style Sets -> New Style Set
2. Select "Select All". Save the file.
3. Select the "User-defined Style Set" radio button. Browse to the style set file you created in the previous step and select it. Click "OK".
This makes Maple use the style set you've defined in future sessions.
(Note that you will need to keep that style set worksheet in its current location. If you move it, the font will go back to its default)
To return to the defaults, go back to:
Format -> Manage Style Sets
and select “Default Maple Style Set”.