To overlap elements, use the CSS z-index property. You can try to run the following code to implement the z-index property and set image behind the text
Example
<!DOCTYPE html>
<html>
<head>
<style>
img {
position: absolute;
left: 0px;
top: 0px;
z-index: -1;
}
</style>
</head>
<body>
<img src = "https://www.tutorialspoint.com/assets/videotutorials/courses/swift_4_online_training/380_course_210_image.jpg" width="300" height="250">
<p>This is demo text.</p>
</body>
</html>