mypmpro-change-seat-text.php

<?php
/**
 * This recipe will change the word 'seat' to 'account'
 * 
 * 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 mypmpro_change_seat_text( $translated_text, $text, $domain ){  

    switch ( $translated_text ) {
        case 'Enter a number from %d to %d. +%s per extra seat.':
            $translated_text = 'Enter a number from %d to %d. +%s per extra account.'
            break;
    }
  
    return $translated_text;

}
add_filter( 'gettext', 'mypmpro_change_seat_text', 20, 3 );