Creating loyalty is not complicated it just requires everyone on board with the vision.

I think they a word there.

“Everyone on board” is slang for everyone agreeing to a way of thinking/doing. The sentence reads correct imo.

Eh, it should probably be “getting everyone on board,” “everyone to get on board,” or “everyone on board agreeing…” It’s missing a verb. I understand it as-is, I just think it’s ungrammatical.

It’s an elision which is common in many English dialects and totally out of place in others. A more common form of this that always feels incomplete to me is “needs washed,” but in both cases, “to be” is elided (omitted).

I’ve heard “needs washed” and also consider it ungrammatical, but I also understand it. So I might say something like “everyone on board” or “needs washed” in conversation, but I wouldn’t do it in writing, especially more formal writing like this where someone is running a business and soliciting work.

While this is writing, it’s not formal, it’s a marketing ad directed less than savvy want to be entrepreneurs… It’s meant to be sales speech.