In your html body tag ,kindly change this and check:
</div>
</body>
<div id ="footer">
<h4>الحقوق محفوظة2021</h4>
</div>
And in CSS made the changes and check:
#footer {
background-color:rgb(191, 208, 240);
text-align: center;
color: black;
padding: 10px 0;
width: 100%;
position:center;
justify-content: center;
}