Samsung Galaxy S III User Manual page 45

3. Double-tap the text.
4. Touch and drag one side of the slider across the screen and highlight the desired text.
Any selected text will appear highlighted.
5. Tap an onscreen option from the Edit text menu bar:

Select All highlights all characters in the text message field.

Cut removes the selected text and saves it to the clipboard.

Paste inserts the clipboard text into the location of the cursor.
Phone Basics 31