The human eye finds it difficult to read multiple typefaces, so we advise clients to stay with a simple collection of fonts, or a family of fonts. If a design is too busy then this causes confusion in the brain as the eye does not know where to look.
Ideally, you want your viewer to have a pleasant experience, so keep to the golden rule of no more than two fonts!
The font needs to reflect your brand. For example, a font that is “fluffy” (such as Brushscript) should not be used for an accountancy practice or a legal firm.