Revise text. Touch and hold the text to show the magnifying glass, then drag to position the insertion point.
Select text. Tap the insertion point to display the selection options. Or double-tap a word to select it. Drag the grab points to select more or less text. In read-only documents, such as webpages, touch and hold to select a word.
You can cut, copy, or paste over selected text. With some apps, you can also get bold, italic, or underlined text (tap B/I/U); get the definition of a word; or have iPhone suggest an alternative. Tap 
to see all the options.
Turn your keyboard into a trackpad. On iPhone 6s and iPhone 6s Plus, press the keyboard until it turns light gray. Move the cursor by dragging around the keyboard. Without lifting your finger, press a little deeper to select a word. Press twice to select a sentence. Press three times to select a paragraph. After pressing, you can drag to select more text.
Undo the last edit. Shake iPhone, then tap Undo.