how to add captcha in form created in wordpress's text editor

I have created a form using wordpress's visual/text editor. I want to include a captcha in this form. But i dont know how to do it. In wordpress, A really simple captcha plugin is already installed but it works with contact form 7 forms only. i tried to copy the [captchac captcha-1] [captchar captcha-1] but it didn't work. Please help me here is the form

<form name="profile" method="post" action="handler.php">
<input type="text" name="customer_name" placeholder="Please enter your namne"/>
<input type="file" name="picture" required/>Please select a picture
</form>