Spelling errors are corrected as you type, unless you turned off the Auto-Correction setting for your iPhone. If you turned off this setting, you can still flag spelling errors as you enter text in Pages documents. You can also add terms to the dictionary so they’re not marked as misspellings.
Note: Spelling is checked according to the language of the keyboard you’re using, not the language of the document.
Tap 
, tap Settings, then tap Auto-Correction.
Turn on Check Spelling, then tap the document to close the controls.
Misspelt and unrecognised words are underlined in red.
Tap a misspelt word, then tap the correct spelling.
Add a word: Tap the underlined word, then tap Learn Spelling (you may need to tap Replace first). The word is added to the dictionary used by Pages and other apps.
Remove a word: Double-tap the word in your document, then tap Unlearn Spelling. The word is removed from the dictionary used by Pages and other apps.
If you can’t see Unlearn Spelling, tap 
, then tap Unlearn Spelling.
Note: If you add a word to the spelling dictionary, it’s added for all languages.
Tap , then tap Settings.
Tap Auto-Correction, then turn off Check Spelling.
If you don’t want words to be corrected as you type, turn off auto-correct. See the task below for instructions.
When auto-correct is turned on, misspelled and unknown words are automatically corrected as you type. Turning off auto-correct applies not only to Pages, but to other apps where you type text, such as Mail.
On the Home screen of your device, tap Settings, then tap General.
Tap Keyboard, then turn off Auto-Correction.