What should I pay attention to so that the voice-over of the artist we choose is suitable for our project?

Yes, this is an important criterion. First of all, if you have a background music, please share it. If there is a video of your project, it will be useful in terms of voice acting. If you do not have any of these, you can write some notes in parentheses about the attitude and style of the voice actor between paragraphs in your text.

For example: At the beginning of the first paragraph: (This place should be read with a somewhat emotional tone) For example: At the beginning of the second paragraph, you can direct the voice actor with notes such as this part could be a little more happy and brisk.