Setting minimum quantity when adding the product to cart from shop page.

functions.php

<?php

function loop_add_to_cart_args_callback( $args, $product ) {

	$product_id  = $product->get_id();
	$product_min = wc_get_product_min_limit( $product_id );

	if ( $product_min ) {
		$args['quantity'] = $product_min;
	}

	return $args;
}
add_filter( 'woocommerce_loop_add_to_cart_args', 'loop_add_to_cart_args_callback', 100, 2 );