Can I add a co-author who doesn't have an Apiway account?

Yes — you no longer need them to register first. Open the photo set on the web, choose their role and share %, and Apiway gives you a private invite code (like K7QX-2M9P). Send that code to the person; they DM it to the @apiway_official bot on Instagram to accept and start earning their share, and the bot signs them up right in the chat (email + a one-time code) if they're new. To invite the same co-author across many photos at once, go to Creators → Photos, select the photos, tap "Add to folder…" to group them under a renameable folder, set the co-author's Instagram handle, role, and percentage share, then tap "Generate invite code" for one code that covers every photo in the folder — and when that person links the same Instagram handle, Apiway asks you to confirm before adding them. Already-registered creators can still be added directly by nickname when you sell or edit the set. If the photo was held because it shows someone else, their acceptance also clears that consent hold.