"I saw your email."
Translation:J'ai vu votre courriel.
It depends where you are (France, Canada, Belgium, Switzerland...) and the context (formal, informal). For instance, in France, nobody uses courriel at all. It sounds extremely unnatural. We can avoid the word email by courrier électronique or simply courrier. On the other hand, in Canada, even though email is widely used informally, in a job context, courriel is preferred.