<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
input{
display: block;
}
div{
margin: 10px 0;
}
</style>
</head>
<body>
<div class="forms"></div>
<button>Добавить</button>
<script>
var i = 0; j=0;
document.querySelector('button').onclick =()=>{
document.querySelector('.forms').insertAdjacentHTML('beforeend',
`<div>Форма ${++j}
<input type="text" id="id${i++}"/>поле 1
<input type="text" id="id${i++}"/>поле 2
<input type="text" id="id${i++}"/>поле 3
<input type="text" id="id${i++}"/>поле 4
<input type="text" id="id${i++}"/>поле 5
</div>`);
};
</script>
</body>
</html>