Add custom logo

// into functions.php
$logo_width  = 120;
$logo_height = 90;
// If the retina setting is active, double the recommended width and height.
if ( get_theme_mod( 'retina_logo', false ) ) {
  $logo_width  = floor( $logo_width * 2 );
  $logo_height = floor( $logo_height * 2 );
}
add_theme_support(
  'custom-logo',
  array(
    'height'      => $logo_height,
    'width'       => $logo_width,
    'flex-height' => true,
    'flex-width'  => true,
  )
);

// Use in theme files
<?php the_custom_logo();?>