A voice-over artist should possess the below five attributes. These will increase your chances of finding a professional who is adaptable, so you can perhaps work with them in the long run. The following qualities are what you should look for in a voice-over actor:

• Voice-acting expertise. Voiceovers need to be reliable enough for their potential client to put their projects in their hands. The voice-over artist must convince the listener that what they are saying and the emotion they are selling are true by showing them the proudest projects and how they can handle the task with their skills and experience.
• The ability to handle different voices and tones. You may want someone who can be both friendly and knowledgeable. More likely to achieve the exact tone you're searching for is someone who can give a variety of various attributes.
• Excellent pronouncing and articulating. Voice performers must speak flawlessly and clearly. The ability to recognize the end of a sentence or thought and to distinguish each individual word must be ingrained implicitly in listeners. 
• The ability to adjust to the right tempo. The pacing of a voice-over is crucial to its quality. The voice-over artist is the one who knows when to sound hurried and disorganized; or when to read it at  a slow tempo to match the script.