[enter image description here][1] [1]: https://i.stack.imgur.com/ONkAu.jpg
function addinfo()
{
var c_name = document.getElementById("c_name").value;
var c_mobile = document.getElementById("c_mobile").value;
var rows_count = document.getElementById("addinfo").rows.length;
$('#addinfo').append('<tr><td><input type="text" name="in_sr[]" id="in_sr" value="'+ rows_count +'" readonly/></td><td><input type="text" name="in_cname[]" id="in_cname" value="'+ c_name +'" readonly/></td><td><input type="text" name="in_cmobile[]" id="in_cmobile" value="'+ c_mobile +'" readonly/></td>');
} table,thead,tr,th,tbody,tr,td{border: 1px solid;}<html>
<head>
<script src="https://cdn.jsdelivr.net/npm/jquery@3.5.1/dist/jquery.slim.min.js"></script>
<style>
table,thead,tr,th,tbody,tr,td{border: 1px solid;}
</style>
</head>
<body>
<label>Name : </label><input type="text" name="c_name" id="c_name">
</br></br>
<label>Mobile : </label><input type="text" name="c_mobile" id="c_mobile">
</br></br>
<button type="button" name="button" onclick="addinfo()">Add Info</button>
</br></br>
<table id="addinfo">
<thead>
<tr>
<th>Sr.</th>
<th>Name</th>
<th>Mobile</th>
</tr>
</thead>
<tbody>
</tbody>
</table>
</body>
</html>