You can use watermark option like this:
[text your-firstname watermark "First Name"]
http://contactform7.com/text-fields/
Contact Form 7 is one of our favorite form plugins because its updated regularly and there are a ton of extensions you can install that make the user-experience that much more rewarding; our favorite is the Database Extension. One feature that people have been asking about for quite some time is the ability to clear the default value of a field onClick or onFocus. This can be done easily by changing a couple lnes of code in the plugin, but remember, when you upgrade Contact Form 7, you’ll need to reapply this change.
On line 89 in this file:
/wp-content/plugins/contact-form-7/modules/text.php
Replace this:
89 $html = '<input type="text" name="' . $name . '" value="' . esc_attr( $value ) . '"' . $atts . ' />';
With this:
89 $html = '<input type="text" name="' . $name . '" value="' . esc_attr( $value ) . '"' . $atts . ' onfocus="if(this.value==\'';
90 $html = $html . esc_attr( $value ) . '\') this.value=\'\';" onblur="if(this.value==\'\') this.value=\'' . esc_attr( $value ) . '\';" />';
And on line 88 in this file:
/wp-content/plugins/contact-form-7/modules/textarea.php
Replace this:
88 $html = '<textarea name="' . $name . '"' . $atts . '>' . esc_html( $value ) . '</textarea>';
With this:
88 $html = '<textarea name="' . $name . '"' . $atts . ' onblur="if (this.value == \'\') {this.value = \'' . esc_html( $value ) . '\';}" onfocus="if (this.value == \'' . esc_html( $value ) . '\') {this.value = \'\';}">' . esc_html( $value ) . '</textarea>';
With those 2 tweaks you should be able to clear the default value each time the user clicks the text field or text area.
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