suppose a new user registered to become a member. You got user's details (name, address etc.) from registration form and saved in database.
Now, when this user logs in, views a play and wants more information, you redirect him to a form.
In this form file you can fetch user details you already entered in the database.
Echo this information in HTML part of the form.
e.g.
(i'm assuming you have user's id when he logs in)
<?php
$query = "SELECT * FROM users WHERE userId = ".$userId;
$resultSet = mysql_query($query, $link); //-- $link is database connection link
$userData = mysql_fetch_array($resultSet);
?>
<html>
<head></head>
<body>
<form action="" method="post">
Name: <input type="text" name="userName" value="<?php echo $userData['userName']; ?>" />
Address: <input type="text" name="address" value="<?php echo $userData['address']; ?>" />
Question: <input type="text" name="question" value="" />
<input type="submit" name="submit" value=" Submit " />
</form>
</body>
</html>