Let's say that you've dictated an email message and a few words got garbled. You can either send the message without correction and maybe give your recipient a laugh or, if it's important to get the message right, then you need to use VoiceOver editing.
VoiceOver can move the insertion point to the start or end of the text with a single finger double tap. Let's try that and double tap until you hear VoiceOver speak "insertion point at start". Turn the rotor until you hear "words". Swipe down to read the document word by word until you hear the first word you want to replace or delete. The insertion point will now be positioned just beyond the last letter of the word. To delete the word, find the delete key on the on-screen keyboard, which is about one third up on the right of the screen. Use the delete key repeatedly to hear the letters of the word deleted one-by-one, in reverse. Now you can enter a replacement word or words using either the keyboard, dictation handwriting or Braille screen input. When you have finished editing, you can check your edit by swiping up and down to listen to the corrected text a word at a time. You may need to make further corrections. Be aware that the insertion point is placed to the right of the word that is spoken if you are swiping down to move forward through the text but that the insertion point is placed to the left of the spoken word if you are swiping up to move backward through the text.
If your text is long and you want to move more quickly to the correction point, then you might set the rotor initially to lines and then change to words when you reach the desired line. The insertion point will be at the end of the line after it is spoken, so you may wish to swipe up once to move the insertion point to the beginning of the line before you turn the rotor to words. If you know you may need to correct errors in some text, then it may be best to read through it line-by-line and make corrections as you go along.
If you can't quite make out VoiceOver's speech, set the rotor to characters to spell the word out character by character. You can delete individual characters if you need to. The character setting on the rotor will let you make minor changes to spellings.
The section on advanced VoiceOver editing describes some more powerful editing tools.