Answer 1

Use
body{
background-image: url("paste the link of the pic here");
}
note: you should modify the www.dropbox.com to dl.dropboxusercontent.com

Answer 2

No Just Unspalsh Works

Answer 3

Just Use In CSS

body{

background-color:pink;

}

Answer 4

https://www.sololearn.com/discuss/2402873/?ref=app
https://www.sololearn.com/discuss/2401922/?ref=app

Answer 5

Well Nevermind

Answer 6

you can learn it from Sololearn css courses there it is available
bg.image{
background-image: url("img link you want to add" );
}