How to add logo on right side of the menu?

Definitely.

Add a menu item to the menu as normal, I’m assuming since it’s the logo of the site you’ll want it to link to the front page.
After you have added this menu item, you’ll need to add some styles to your child theme or via a style plugin.
Find the ID of the link li, it will be something like #menu-item-1 where the number could be any whole number really.

Then add this style:

/*Add background image to the list item*/
#menu-item-1 {
    background-color: transparent;
    background-position: center center;
    background-image: url('images/logo.png');
    background-size: 25px 25px;
}

/*Hide link text*/
#menu-item-1 a,
#menu-item-1 a:hover {color:transparent}

Adjust the styles to your specifications.