If you need a partner, make sure you post on the dedicated
Quests - Heroes' and Arrav
thread, as this will help you find a partner on OSRS. I recommend that you read back through the last few posts, to see if you can contact someone to help them. You could also join the 'OSRS SoA' friends chat, as it's quite active.
If you're playing RS3, you can now complete both the Heroes' Quest and The Shield of Arrav without a partner.
Thread has been locked, as there is no need for it to continue. Please refer to Trewavas' helpful advice above, whether you're playing RS3 or OSRS. Thank you!