I work with both private customers and architects/designers. Once I have been contacted by a potential customer, I arrange a face-to-face meeting, usually on site.
If I am contacted by an architect/designer, the process is simpler in that they will usually have a plan of a kitchen, say, and often elevational drawings as well and they will simply ask me to price the job.
In the case of private customers, some will know exactly the style, materials and layout of a particular project and they will just want to know what it will cost; others will ask me to design the project from scratch. I provide a free service in meeting, discussing, pricing and drawing up what has been discussed.