how can I limit guests control? e.g. I don't want them to be able to invite others to the board

[Elham]

I I have my team which includes the partners. and I added freelancers as guests to the boards. But I can't control their access. There is one option, to make them an observer. However in this case, they can't move the cards. so if I have "Things to do" "doing" and "done", they cant move a card to done when they finish the job. so I have to add them as members.  I even upgraded to business class. but I still don't see the option to NOT LET THEM ADD OTHERS 

[Stephen Addis]

Any other controls above that, like read only tends to be a feature of the business level accounts that they charge for per month per user.

They play on the fact if you want total control, its chargable.

[Iain Dooley]

@Elham you can disable the ability for non-admins to invite others:

https://help.trello.com/article/791-changing-permissions-on-a-board