Ask How do you write a contract clause that protects you if a client changes the project scope?

[Edward22]

I have noticed that clients sometimes ask for extra work after a project has already started, even when it was not part of the original agreement. This can make the work longer and more stressful without extra pay. I understand that a contract clause is a written rule in an agreement that explains what happens in such cases. I want to avoid confusion from the start, so how do you write a clear clause that protects you when a client changes the project scope?