Thank you for giving a reply to me. I followed the below link
Disable browser ‘Save Password’ functionality
I resolved the issue by just adding readonly
& onfocus="this.removeAttribute('readonly');"
attributes besides autocomplete="off"
to the inputs as shown below.
<input type="text" name="UserName" autocomplete="off" readonly
onfocus="this.removeAttribute('readonly');" >
<input type="password" name="Password" autocomplete="off" readonly
onfocus="this.removeAttribute('readonly');" >
This is working fine for me.