pmpro-restrict-by-allowed-specific-countries-per-level.php

<?php
/**
 * Require user to reside in specific countries to register for specified membership levels.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_init_pmpro_allowed_countries_per_level() {
	global $allowed_countries;

	//specify the countries allowed to signup. The key is the level id.
	$allowed_countries = array(
		1 => array( 'US' ), // Add the allowed countries for level 1
		2 => array( 'US', 'CA' ),      // Add the allowed countries for level 2
	);
}

add_action( 'init', 'my_init_pmpro_allowed_countries_per_level' );

function my_pmpro_registration_checks_allowed_countries( $continue_registration ) {
	global $allowed_countries, $pmpro_msg, $pmpro_msgt;

	$country  = $_REQUEST['bcountry'];
	$level = pmpro_getLevelAtCheckout();
	$level_id = intval( $level->id );

	//only check if the level has allowed countries specified
	if ( array_key_exists( $level_id, $allowed_countries ) && ! in_array( $country, $allowed_countries[ $level_id ] ) ) {
		$pmpro_msg  = 'Your country of residence is not permitted to register for this level.';
		$pmpro_msgt = 'pmpro_error';
		return false;
	}

	return $continue_registration;
}
add_filter( 'pmpro_registration_checks', 'my_pmpro_registration_checks_allowed_countries' );

function my_pmpro_level_expiration_text_allowed_countries( $text, $level ) {
	global $allowed_countries, $pmpro_countries;

	if ( array_key_exists( $level->id, $allowed_countries ) ) {
		$text = $text . ' This level can only be purchased if you reside in the following countries: ';

		//code for commas
		$i     = 1;
		$count = count( $allowed_countries[ $level->id ] );
		foreach ( $allowed_countries[ $level->id ] as $country ) {
			$text = $text . $pmpro_countries[ $country ];

			if ( $i < $count ) {
				if ( $i == $count - 1 ) {
					$text = $text . ', or ';
				} else {
					$text = $text . ', ';
				}
			}

			$i++;
		}

		$text = $text . '.';
	}

	return $text;
}
add_filter( 'pmpro_level_expiration_text', 'my_pmpro_level_expiration_text_allowed_countries', 10, 2 );

To restrict all level by country use https://gist.github.com/ipokkel/f9dcbae02131bcf232d9371dbda7e641