As long as you finish your daily reviews, any time is fine. Some people do Anki first thing in the morning, some spread their reviews throughout the day. The worst option would be to do Anki in the evening when you're tired.
I personally try to do Anki in the morning. By dedicating myself fully to finishing my daily reps in one continuous chunk of time, I can finish them faster. To have as little distractions as possible, I usually use a dedicated device (a laptop) with only Anki installed/running.