Hi makenzi.exc,
Use the toLocaleString method and set the timeZone property.
Refer below example.
HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style type="text/css">
body { font-family: Arial; font-size: 10pt; }
</style>
</head>
<body>
<input type="button" value="Submit" onclick="IndianDateTime()" />
<script type="text/javascript">
function IndianDateTime() {
var dt = new Date(Date.UTC(2025, 02, 07, 01, 35, 25));
alert("UTC DateTime of " + dt.toUTCString() + " is\n"
+ dt.toLocaleString("en-IN", { timeZone: 'Asia/Kolkata' }) + "IST");
};
</script>
</body>
</html>
Demo
Screenshot

Downloads
Download Sample