In some areas only plans from an architect can be used. Other places only for buildings over a certain size or usage has to be sealed by an architect.

In some areas they can be sealed by an engineer. Other require an egineer.

Some places don't require either.

Some places don't have any building permits at all.

The capability of builder vary a lot. Some can only work from full detailed plans.

Other, often called design build, can either flush out the plans and/or work with an architect or drafter to finialize the plans.

But, thanks for reply. Please tell me how do I find out what is permitted in any place I might want to have it built? Would that be the town's code officer or other?

One problem is that the name can vary.

It could be code office, but in some case that has to with maintance codes (uncut grass and broken windows) and with building codes.

Most likely it will have Building in the name.

And in someplace the firedepart or maybe a county office handles this.

Also, insome places Zoning or Land Usge might be envolved. There are other issues such as setbacks and percentage of land covered by buildings that sometimes come into play.

If you can't find them then call the Mayors or City Adminstrators office. They should be able to direct you in the right direction.