The most important factors to keep in mind when photographing artwork are the following:
Keeping the camera parallel to the artwork
Having consistent lighting across the artwork
It is often best to use a tripod to stabilize the camera and shoot in RAW to be able to adjust the white balance when post processing. I will show three ways to photograph artwork:
Using a mirrorless camera (Fujifilm X-Pro2 with Fujifilm 35mm f/2 lens)
Using an iPhone X and ProCam to photograph in RAW
Using an iPhone and the Apple Camera App
Setting up the scene
This approach will be similar if using any mirrorless camera, Digital SLR or even the camera on your phone.
You can attempt to hand hold the camera or phone but it may be difficult to keep it steady enough to avoid motion blur unless there is a lot of light. For basic use cases, handholding a phone in good light should be sufficient but if you would like to improve the production quality, using a mirrorless camera or digital SLR in good light will help.
Mirrorless Camera
Mobile Phone
The mobile phone setup will be similar to the mirrorless camera setup. Place it on a tripod or find someway to stabilize the phone while keeping the face of the phone parallel to the artwork. This could be as simple as resting it on top of another tripod or piece of furniture if you do not have a phone holder tripod attachment.
Hopefully this post was useful in providing various options to photograph Artwork.