It depends on the type of workflow you have set up, the trigger that you’re using and the capabilities of the apps you're connecting.
Polling triggers look for new information from your trigger app once every 1 to 15 minutes. The polling time for your Zaps varies based on your subscription plan. Instant triggers run each time new information comes in directly from your trigger app.
If you want your Zap to run at a specific time, you can set up a scheduled trigger.
Alternatively, if you want your actions to run after a certain period of time, rather than instantly, you can add a delay to your Zap.