Not 100% sure what you're asking...
I assume that you have a field in a database, which you have extracted, and you want to present it to the user, so that they can edit it. If you have called the string $dbfield, then you can display that to the user in a form using the 'value' attribute of a form element, eg
<input type="text" name="author" value="<? print($dbfield); ?>">
Your variable will then appear in the text box by default. If the string is longer, and you are using the textarea tag, you use something like:
<textarea name="address"><? print($dbfield); ?></textarea>
Is that what you were after?