If you have an Advantage subscription, sign onto your Advantage account to download the 2020 desktop software - https://accounts-tax.intuit.com/turbotaxadvantage

You can check the order status here:

https://turbotax.intuit.com/personal-taxes/cd-download/order-status/

However the online purchase system is still in Pre-Order so it may be a couple more days. They have not updated the FAQ yet from last year's info :  

See this TurboTax support FAQ on when to expect your Advantage order - https://ttlc.intuit.com/community/choosing-a-product/help/when-can-i-expect-to-receive-my-turbotax-a...