The spell check feature in most word processors can be enabled in the program's settings. For Microsoft Word, this can be found under the 'Proofing' tab in the 'File' menu. In the 'Proofing' options, make sure the 'Check spelling as you type' and 'Mark grammar errors as you type' boxes are both checked. For Google Docs, spell check can be enabled by going to the 'Tools' menu and selecting 'Spelling.'