When performing any work on electrical systems, it is critical to have the correct tools and safety equipment and to use your tools in the manner prescribed.
Before beginning work, test the circuit to confirm it is live, then turn off the circuit breaker in your electrical panel, then test the circuit again to confirm it is dead.
If you cannot confirm the correct breaker, or if you are not confident in your safety equipment, you can de-energize the entire electrical system by turning off the main breaker.
Outlet and switch cover plates may seem like they are primarily decorative, they provide protection against an electric shock and are an important part of electrical safety.