new const r_user_file[] = "user.ini"
new r_iFile[64], r_iDir[64]

public Твоя_функция(id)
{
// .. твой код

// Пример:
new nick[33]
get_user_name(id, nick, charsmax(nick))
new const pass[] = "qwert1234567"
new const pflags[] = "abcd"
new const acc_flags[] = "a"

get_configsdir(r_iDir, charsmax(r_iDir))
formatex(r_iFile, charsmax(r_iFile), "%s/%s", r_iDir, r_user_file)

new filetext[256]
format(filetext, 255, "^"%s^" ^"%s^" ^"%s^" ^"%s^"", nick, pass, flags, acc_flags)
if(file_exists(r_iFile))
write_file(r_iFile, filetext, -1)
}

new const r_user_file[] = "users.ini"
new r_iFile[64], r_iDir[64]

public Твоя Функцыя(id)    
{    
    new nick[33]    
    get_user_name(id, nick, charsmax(nick))    
    new const pass[] = "ПАРОЛЬ"
    new const pflags[] = "ФЛАГИ"
    new const acc_flags[] = "a"
    get_configsdir(r_iDir, 63)
    formatex(r_iFile, charsmax(r_iFile), "%s/%s" , r_iDir, r_user_file)    
    new filetext[256]    
    format(filetext, 255, "^n^"%s^" ^"%s^" ^"%s^" ^"%s^"", nick, pass, pflags, acc_flags)    
    if(file_exists(r_iFile))    
    write_file(r_iFile, filetext, - 1)
    server_cmd("amx_reloadadmins");    
}