Hello there, Cindy.
I'd like to gather a bit more information to guide you to the right solution. Are you recording purchases/expenses where you'll claim the 50% GST rebate from CRA, or are you dealing with sales transactions? Currently, QuickBooks Online Canada doesn't have a built-in tax code that automatically splits GST between an expense account and GST Payable.
However, you can consider creating group rates as a workaround so you can apply multiple taxes in each line item within a transaction. If you set one tax rate mapped to a liability account for the rebate and another tax rate mapped to an expense account, grouping them will create the split you need.
Refer to this article for the detailed steps in grouping tax rates: Add a group sales tax rate in QuickBooks Online.
However, since this involves complex tax treatment specific to nonprofit accounting, I also encourage consulting your accountant to ensure compliance with CRA requirements.
Feel free to reply below if you have further concerns.
