Copyright law grants the creator of an original work exclusive rights over the use and distribution of those works. This right is created by the United States Consitution.
Article I, Section 8, Clause 8 of the United States Constitution, known as the Copyright Clause, empowers the United States Congress: To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.
All that is required to obtain a copyright is to create an original work of authorship fixed in any tangible medium of expression. 17 U.S.C. §102 That medium need not be in writing, but may in many forms. The following are listed by the Copyright Act:
The list is not exhaustive. Many new forms of expression are protected under copyright law including computer source code, compiled object code, UI/UX designs, flowcharts, UML diagrams, and many other digital artifacts that are commonly developed through software engineers and designers.
What is important to understand is that copyright does not protect ideas, only the manifestation of them. If you want to protect an idea, than reduce it to writing! Otherwise you will need to obtain a patent on the concept.