Voice actors aren't just people who can make funny voices. They are real actors that bring credibility to the characters they play. While voice acting is primarily done in animation, video games and children's cartoons, the characters they portray are treated as real people. Characterization is an important skill for aspiring voice actors to learn so they can create memorable characters that are more than their voices.
Professional voice actors have busy workdays entailing multiple recording sessions. Each of these sessions is usually several hours long. Before performing their scenes, the actors meet with the director and go over the script. Scripts are usually read for the first time on location. This means that the actors must be able to produce a worthy performance on short notice.
Once they go over the script and talk with the director, the voice actors enter a sound studio. Sound studios are designed with two rooms -- a recording booth and a control room. In the booth, the actor reads the script alone or with other scene actors. In the control room are the director and sound engineer, who listen and provide feedback for the actors. There may be many takes until the director is satisfied.
Sometimes voice actors are tasked with voicing multiple characters. The actors create voices through observation and mimicry. Once an actor develops a new voice, she has to practice it regularly in case the director asks for tweaks or if future opportunities to portray the character come up.
Voice actors are freelancers with inconsistent schedules and pay. The U.S. Bureau of Labor Statistics doesn't cite an average salary, but most are paid hourly at rates of $300 to $500 for the first hour and $250 to $350 for every hour after that. These rates are subject to negotiation, however, especially on long-term projects.