You can’t use TurboTax CD/Download codes in the TurboTax mobile app (or TurboTax Online) and vice-versa.
If you have a Chromebook, you can use TurboTax Online to prepare your returns. We don’t have a 20 return package for TurboTax Online. But we do have an 8-return standard package which you can find on the right here: https://turbotax.intuit.ca/x/offers/turbotax-standard.jsp?src=care&cnm=care_fy20_tto_8
If you need a refund, you can use the form on this page to request one: https://turbotax.community.intuit.ca/community/after-you-file-questions/help/how-do-i-get-a-refund-for-a-turbotax-product/00/873559