Use <label>
tag before <input>
like this.
<label>Email Adress:
<input type="text">
</label>
This is a simple method to do this. You can simply omit the use of the submit button if you don't need it to show.
Here is the modified code of yours.
<div id="psform">
<?php $search_text = "Search"; ?>
<form method="get" id="searchform" action="<?php echo home_url(); ?>">
<label>Email Adress:
<input type="text" value="<?php echo $search_text; ?>" name="s" />
</label>
</form>
</div>
Edit:
If you want to add a title to the search form, you can use any heading tag. If you need any other help, please don't hesitate to ask.