If you are not using any javascript/jquery for form validation, then a simple layout for your form would look like this.
within the body of your html document:
<form action="formHandler.php" name="yourForm" id="theForm" method="post">
<input type="text" name="fname" id="fname" />
<input type="submit" value="submit"/>
</form>
You need to ensure you have the submit button within the form tags, and an appropriate action assigned. Such as sending to a php file.
For a more direct answer, provide the code you are working with.
You may find the following of use: http://www.w3.org/TR/html401/interact/forms.html