how to have a text background color in html code example

Example 1: fill color behid text in html

Put the text in an inline element, such as a <span>.

<h1><span>The Last Will and Testament of Eric Jones</span></h1>
And then apply the background color on the inline element.

h1 {
    text-align: center; 
}
h1 span { 
    background-color: green; 
}
An inline element is as big as its contents is, so that should do it for you.

Example 2: fill color behid text in html

Option 1
display: table;

no parent required
h1 {
    display: table; /* keep the background color wrapped tight */
    margin: 0px auto 0px auto; /* keep the table centered */
    padding:5px;font-size:20px;background-color:green;color:#ffffff;
}
<h1>The Last Will and Testament of Eric Jones</h1>