You enter characters into the IME by typing in roman letters.  The IME can automatically convert these to hiragana or katakana, depending on the input mode you select.  You select the mode by clicking on the "Input Mode" button on the IME toolbar.  This gives you several input options:

The input options are as follows:

• Hiragana - Characters are entered in hiragana.  During the entry phase, you can convert the entered hiragana characters to kanji or katakana.
• Katakana - Characters are entered in katakana.  During the entry phase, you can convert the entered hiragana characters to kanji or hiragana.
• Full-Width ASCII - Characters are entered in full-width ASCII.  Note that this is not the same a normal input - Japanese character codes are used.  If you send a document containing these characters to a friend he won't be able to see them  unless he has the Japanese language support on his computer.
• Half-Width Katakana - Characters are entered in half-width katakana.  During the entry phase, you can convert the entered hiragana characters to kanji or katakana.
• Half-Width ASCII - Characters are entered in half-width ASCII.  This is slightly different than "direct" input mode below, because characters are entered using Japanese code and a fixed-width font.  If you send a document containing these character to a friend, he won't be able to see them unless he has the Japanese language support on his computer.
• Direct Input - Characters are entered directly, bypassing the IME.  This is the same as turning the IME off altogether.