In this example we change the position of update cart button before checkout button in Cart page.

Put the below code in functions.php page

add_action('woocommerce_cart_totals_after_order_total', 'change_update_cart');

function change_update_cart(){
	?>
	
	<button type="button" class="button" name="update_cart" value="<?php esc_attr_e( 'Update cart', 'woocommerce' ); ?>" id="new_update_btn"><?php esc_html_e( 'Update cart', 'woocommerce' ); ?></button>
	<?php
}

In cart.php file find this code for update cart button

<button type="submit" class="button" name="update_cart" value="<?php esc_attr_e( 'Update cart', 'woocommerce' ); ?>" id="main_update_btn" style="display: none;"><?php esc_html_e( 'Update cart', 'woocommerce' ); ?></button> 

style=”display: none;” Add this code for hiding the woocommerce default button.

Now just put js code in footer.php

<script>
jquery('#new_update_btn').on('click', function(event) { 
  jquery('#main_update_btn').trigger('click');

});
</script>