Make specific parts of a text clickable in flutter

You can use RichText to merge a list of TextSpan into a single Text.

    return RichText(
      text: TextSpan(
        text: 'Hello ',
        style: DefaultTextStyle.of(context).style,
        children: <TextSpan>[
          TextSpan(
              text: 'world!',
              style: TextStyle(fontWeight: FontWeight.bold)),
          TextSpan(
              text: ' click here!',
              recognizer: TapGestureRecognizer()
                ..onTap = () => print('click')),
        ],
      ),
    );

Use RichText with TextSpan and GestureRecognizer. With GestureRecognizer you can detect tap, double tap, long press and etc.

Widget build(BuildContext context) {
    TextStyle defaultStyle = TextStyle(color: Colors.grey, fontSize: 20.0);
    TextStyle linkStyle = TextStyle(color: Colors.blue);
    return RichText(
      text: TextSpan(
        style: defaultStyle,
        children: <TextSpan>[
          TextSpan(text: 'By clicking Sign Up, you agree to our '),
          TextSpan(
              text: 'Terms of Service',
              style: linkStyle,
              recognizer: TapGestureRecognizer()
                ..onTap = () {
                  print('Terms of Service"');
                }),
          TextSpan(text: ' and that you have read our '),
          TextSpan(
              text: 'Privacy Policy',
              style: linkStyle,
              recognizer: TapGestureRecognizer()
                ..onTap = () {
                  print('Privacy Policy"');
                }),
        ],
      ),
    );
  }