Hey @Serhii,
Thanks for using the dev forum!
We are hoping to have some documentation in Swift for this feature soon. In the meantime, I am here to help you 
There is another developer who is starting to integrate custom ui in Swift right now. Can you check out our conversation here: I want to add a custom button in the meeting option toolbar in my zoom app in ios. I see there are provisions to hide or show the toolbar or even specific buttons. But is there any way to add a custom button in the toolbar under more in IOS? - #9 by Michael_Condon
Thanks!
Michael