When it comes to editing text on my iPhone (in, for example, an email text or the Google search box), my pet peeve is the process required to fix a typo. I am not adept at tapping the screen to place the cursor where I want to make an edit or pressing and holding until the circular magnifier tool pops up. There is, however, a better way.
To turn your keyboard into a trackpad, 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. [For iOS 11 and later with 3D Touch enabled]
From iPhone User Guide