how we can align a form input box at center?

Answer 1

<div align="center">
<form>
<input>
</form>
</div>

Answer 2

<style>
form input{
display:block;
width:300px;
margin: auto auto;
}
</style>

<form>
<input />
</form>

Answer 3

<div style="text-align:center;">
<form>
<input>
</form>
</div>