This question already has an answer here:
When you click the download button it opens the file in another tab instead of downloading it.
Files: Image
Both files are in the same folder.
<!DOCTYPE html>
<html>
<head>
<title>TEST</title>
</head>
<body>
<a href="test.txt" target="_blank" download="test.txt">Download</a>
</body>
</html>