My Indesign program does not recognize Impactful as a word. I thought I was just spelling it wrong so I looked it up.

Impactful

The adjective impactful, a late-20th-century coinage, is frequently derided as a meaningless buzzword, but the word is here to stay whether we like it or not, and many people find it useful.

The main gripe is that impactful is illogical because the suffix –ful means full of, and impact is not a quantity and hence can’t fill anything. The problems with this complaint are (1) that –ful also means having the quality of, and that (2) impact bears the secondary sense the power to make an impression, and such power can be a quantity.

-http://grammarist.com/words/impactful/