The bad news - it's not directly possible. The good news - there is a pretty simple workaround.
Primarily, Zapier is a tool that works in realtime. Once a zap is switched on - say to watch new orders in a tool like Shopify or WooCommerce - it will either wait for new order data to be sent to it, or it will periodically check for new orders and pull back the data (this describes the two types of trigger).
What this means is that any orders that happened before the zap was switched on are effectively invisible - meaning syncing historical data isn't possible.
However, if you don't mind a little extra setup, then it's possible using Google Sheets (or Excel or Airtable).
If yours does, download it.
Create a blank Google Sheet and then make sure it has all the same columns and in the same positions and with the same headers as the CSV file you just exported. Paste one example record from the CSV into the Google Sheet.
Create a new zap. The trigger should be a new Google Sheet row. The action step should be creating a record in what ever your end goal app is. Test it using the example row you added from the Google Sheet.
Once built, you can switch the zap on. Next start pasting rows from your CSV into the Google Sheet to trigger the zap. Just be sure to do it in batches of 100 or less, otherwise you'll trigger Zapier's flood protection.
We'll be the first to admit when Zapier isn't the best tool for the job, and for syncing historical data, Zapier isn't really. When searching for possible alternatives, we found a few.
Hull is a customer data platform that unifies data from leading SaaS tools and data warehouses. Customer attributes are stored in their database indefinitely and events are stored for 90 days (or longer if needed). The Hull team recently released a Zapier connector that triggers Zapier workflows using historical data from Hull.
Next, Flatly is a neat tool that does basically the workflow we've described above, but wrapped inside a nice user interface to make it easier to manage.
Another one to try is Piesync, which is more of a set-it-forget-it tool, which lets you pick combinations of two apps from a ever growing menu, after which PieSync will handle a two-way historical and ongoing sync of records between them.