1. Log in to blogger account and Go to Design > Edit HTML
2. Put checked marked in Expand Widget Templates
3. Find this tag by using Ctrl+F ]]></b:skin>
4. Paste below code Before ]]></b:skin> tag
#subsfeed {
background: #616161 url(#);
width:260px;
height:45px;
}
.subsfeed_field{
width:200px;
height:18px;
border:2px solid #6ca408;
margin:13px;
float:left;
}
.subsfeed_button{
width:24px;
height:24px;
background:transparent url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZhPhZO7K0iQRAMPM5N5M7Wckyl-iNKgHXtcr6tI2uG11xTcr09nXR6gH9IULRc8jnl0T-9oISbeF_qcM0IsYZuWZG9nLgIp9BmeFeuZlUh5ArMLNJ80uAos4HXHiRalbFrGMXpWrc0YOK/s1600/arrow.png);
border:0px;
margin:13px 0 0 2px;
cursor:pointer;
float:left;
} 5. Now Go to Design >>page Element
6.Click Add gadget and Select HTML/JavaScript
7. Now paste paste below code
<div id='subsfeed'>
<form action='http://feedburner.google.com/fb/a/mailverify' method='post' onsubmit='window.open('http://feedburner.google.com/fb/a/mailverify?uri=Feedburner URL',
'popupwindow', 'scrollbars=yes,width=500,height=520');return true' target='popupwindow'><input class='subsfeed_field' name='q' onblur='if (this.value == "")
{this.value = "Enter Your E-mail...";}' onfocus='if (this.value == "Enter Your E-mail...") {this.value = "";}' type='text' value='Enter Your E-mail...'/>
<input name='uri' type='hidden' value='Feedburner URL'/><input name='loc' type='hidden' value='en_us'/><input class='subsfeed_button' type='submit' value=''/></form></div>
Replace Feedburner URL with your Feedburner URL
8. Now save HTML/JavaScript.
you are done.

