Copyright protects your work and prevents others from using it without your permission.
Most copyright safeguards are automatic and free, and you can simply mark your work with the copyright symbol  if you wish.
From the instant you finish your creative work, it’s automatically copyrighted as yours. However, registering a copyright is recommended because it establishes a record that you claimed the copyright. This can be a big help in any copyright disputes.
In the US, the standard fee to register copyright with the Copyright Office is over $50. It costs less if you’re registering only one item, you’re the sole credited creator, and you didn’t create it as part of your job.