Unless, your Bookkeeper has TurboTax software you cannot send him a .tax file of your return. You would need to save your Online return as a PDF file, then you can email it to him, which he can open in Adobe Reader. Just know that emailing a tax return is not safe.
How do I save my 2019 TurboTax Online return as a PDF?
https://ttlc.intuit.com/community/saving/help/how-do-i-save-my-turbotax-online-return-as-a-pdf/00/26234