How to promote and monetize on Whatsapp/Telegram groups?

More and more people using all sorts of messenger groups today. Be it for edgy memes, your anime addiction or your next travel deal. I see alot of potencial but I was wondering

1. how do you promote your group?
2. Can you get "fake" users so the group looks massive to new people joining?
3. How do you monetize these groups?

just cross promote with other group owners or simply invite your users to join your telegram group in any social media or blog post.

You can also buy fake users, just be aware of their quality. A bunch of strange usernames with arab or chinese fonts won't feel legit for incoming users.

Whatsapp only allows limited number of users per group. Telegram has much more potential.

WhatsApp is strict with promotions, it will ban the account. Telegram is much better option.