Change the words like 'Membership' to 'Subscription' by Level in Checkout Emails in Paid Memberships Pro

pmpro-changing-membership-wording-level.php

<?php
/**
 * Dynamically replace instances of "Membership" with custom labels
 * based on the user's membership level. Variables like !!first_name!!
 * are preserved and skipped during replacements.
 *
 * 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.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_gettext_membership_dynamic( $translated_text, $original_text, $domain ) {
	if ( is_admin() || ( $domain !== 'paid-memberships-pro' && strpos( $domain, 'pmpro-' ) === false ) ) {
		return $translated_text;
	}

	$current_user_id = get_current_user_id();
	if ( $current_user_id ) {
		$level = pmpro_getMembershipLevelForUser( $current_user_id );
		if ( $level ) {
			$level_id = $level->id;

			// Split by PMPro variables so we don't touch them (e.g. !!membership_level_name!!)
			$segments = preg_split( '/(!![^!]+!!)/', $translated_text, -1, PREG_SPLIT_DELIM_CAPTURE );
			$processed = '';

			foreach ( $segments as $segment ) {
				if ( preg_match( '/^!![^!]+!!$/', $segment ) ) {
					$processed .= $segment; // Don't change PMPro tokens
				} else {
					// Level 1:
					if ( $level_id == 1 ) {
						$segment = str_replace( ['Membership', 'membership'], ['Enrollment', 'enrollment'], $segment );
					}
					// Level 2: 
					elseif ( $level_id == 2 ) {
						$segment = str_replace( ['membership account', 'membership'], ['account', 'account'], $segment );
					}
					// Level 3+ (3 and above):
					elseif ( $level_id >= 3 ) {
						$segment = str_replace(
							['Membership Level', 'membership level', 'Membership', 'membership'],
							['Subscription', 'subscription', 'Subscription', 'subscription'],
							$segment
						);
					}
					$processed .= $segment;
				}
			}

			return $processed;
		}
	}

	return $translated_text;
}
add_filter( 'gettext', 'my_gettext_membership_dynamic', 10, 3 );

function my_ngettext_membership_dynamic( $translated, $single, $plural, $number, $domain ) {
	return my_gettext_membership_dynamic( $translated, $number == 1 ? $single : $plural, $domain );
}
add_filter( 'ngettext', 'my_ngettext_membership_dynamic', 10, 5 );