You can add some CSS using a custom CSS plugin:
.site-info {
display: none;
}
#colophon:after {
content: 'Copyright 2016 Acme Anvil Company';
color: white;
font-size: 16px;
display: table;
margin:0 auto;
height: 70px;
}
The first rule hides the existing copyright info, the second rule adds your own info. Make changes to the property values as you see fit.
Alternately, you can create a child theme. You don’t want to modify the theme files directly, or else your changes will be lost the next time you update/upgrade the theme (which is why I recommended using a CSS plugin earlier if you plan on taking that route).
Then, in your child theme, make a copy of the parent theme’s folder.php file. Edit the file and look for these lines:
<div class="site-info container">
<a href="<?php echo esc_url( __( 'https://www.ads-software.com/', 'west' ) ); ?>"><?php printf( esc_html__( 'Proudly powered by %s', 'west' ), 'WordPress' ); ?></a>
<span class="sep"> | </span>
<?php printf( esc_html__( 'Theme: %2$s by %1$s.', 'west' ), 'aThemes', '<a href="https://athemes.com/theme/west" rel="designer">West</a>' ); ?>
</div><!-- .site-info -->
Replace the middle three lines with your copyright statement.