How do you spell edjucation?

Because the proper spelling is education. The syllable sounds are (ed-yoo-KAY-shun). Whether or not it follows the rules of pronunciation, that is how the etymological development has proceeded.

However, there could be reason for those not familiarwith the correct spelling to misspell it. In forming the ed-yoo bridge, the lips form the same sound as the English letter J. This creates the sounds eh-joo instead. As most spellers know that the Word starts with ED, they spell the following syllable phonetically as JU and create the pronunciation (eh-joo-KAY-shun).