Your clients' ability to see the budget is set up in the project's Setup page (Main Menu > "i" info icon next to your project > Edit Project Setup > Client Access).
By default in a fixed price project your client would not have access to the budget, whereas in an open book project, they would. However, you’re always free to change this setting by project based on that job’s specific needs.
Clients will never have access to your estimate page. Access to the estimate is reserved to your builder users with “edit financial” permissions for inputting the budget information.
Partners cannot see any budget or estimate information in the system.