Architects design buildings, they are highly specialised at this task and can design a building taking into account many competing priorities.
Yes, an architect is a protected title and you must be registered with an architectural board in your state to be able to use the term.
The total time to have an architect design a home can range from a few weeks for a very small and simple plan through to many months for an extensive design with lots of consultation.
Your job as a client is to be clear about what you aim to achieve, what you need and desire and what budget is set for your project. You need to ask questions to make sure you understand the drawings and designs and also what costs are involved.
There are no set fees in regard to the cost for an architect to design a house. You can ask the architectural firm for a layout of the fees you project is to incur so that way you can understand the costs before proceeding.