Hello,
As you can see there is title “Sign In” in the code:
<?php if(class_exists('Woocommerce')): ?><li class="login-link"><a href="<?php echo get_permalink( get_option('woocommerce_myaccount_page_id') ); ?>"><?php _e( 'Sign In', ETHEME_DOMAIN ); ?></a></li><?php endif; ?>
so it edits Sign In link.
Have you created child theme?
Create it and create functions.php file inside the child theme folder.
Again if you have difficulties would be better if you hire a developer.
Regards,
Eva Kemp.