If you tap the Cap button once (looks like a filled arrow pointing up) that should allow you to insert a capital letter any time. If you tap it twice, it turns on Caps Lock, which should allow you to type in all caps until you turn it off. If the keyboard is autocorrecting the word, you should see that word, without corrections, listed in the suggestions bar... just tap the one with the correct capitalization to continue typing the next word (or turn off autocorrect altogether).