JSFiddle - React, Tailwind, and code Playground

HTML

<div data-role="page" id="lastpage">
    <div data-role="header" data-theme="b">
        	<h1>Test</h1>

    </div>
    <div data-role="content">
        <form method="post" action="/url">
            <div data-role="fieldcontain">
                <label for="name">Name :</label>
                <input type="text" name="name" id="name" value="" />
            </div>
            <div data-role="fieldcontain">
                <label for="phone">Phone :</label>
                <div class="input-prepend">	<span class="add-on">+91</span> 
                    <input type="number" name="phone" id="phone" value="" />
                </div>
            </div>
            <input type="submit" value="Submit" data-theme="b" data-inline="true" />
        </form>
    </div>
    <div data-role="footer" data-theme="c">
        	<h5>Footer</h5>
    </div>
</div>

CSS

.input-prepend {
    display: inline-block;
    font-size: 0;
    margin-bottom: 10px;
    vertical-align: middle;
    white-space: nowrap;
    border-radius:0.6em;
}
.input-prepend .add-on {
    background-color: #EEEEEE;
    border: 1px solid #CCCCCC;
    display: inline-block;
    font-size: 14px;
    font-weight: normal;
    height: 20px;
    line-height: 20px;
    min-width: 16px;
    padding: 7px 5px;
    text-align: center;
    text-shadow: 0 1px 0 #FFFFFF;
    width: auto;
}
.input-prepend .add-on {
    vertical-align: bottom;
    border-radius:0.6em;
}