Add the following code in your child theme’s functions.php

add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles', PHP_INT_MAX);

function theme_enqueue_styles() {
	wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
	wp_enqueue_style( 'child-style', get_stylesheet_directory_uri() . '/style.css', array( 'parent-style' ) );
}

Then add styles in your style.css file