Discussion in css for spacing

#header{
background-color:red;
height: 70px;
}

#banner{
background-color: orange;
height: 90px;
overflow: hidden;
}

#intro{
background-color: pink;
height: 90px;
}
#box1{
background-color: darkolivegreen;
height: 300px;
width: 32%;
margin-right: 2%;
float: left;
padding-bottom: 20px;
}
#box2{
background-color: brown;
height: 300px;
width: 32%;
margin-right: 2%;
float: left;
padding-bottom: 20px;

}
#box3{
background-color: rgb(47, 95, 107);
height: 300px;
width: 32%;
float: right;
padding-bottom: 20px;
}

#footer{
background-color: darkkhaki;
height: 100px;
margin-top: 20px;
clear: both;
}

I want space before footer, i have given padding still its not working

Can you share your html too? Maybe a codepen or something

Kindly do share your HTML code too as @ilenia says,

Then only we will be able to help you !!

Hope you understand !!