Your tax return is contained in its own data file, like a spreadsheet or word processor document. The name should be something like "John Smith 2023.tax2023" and it should be somewhere in your Documents folder.
Find your tax data file and make as many copies as you want, then make changes in the copies. Keep the original in a safe place and don't change the original.
yes for H&B desktop . however, each file needs to be saved with a unique name
you real return could be save as "FOR FILING" another could be saved as HOME SALE"
the unique names is so you don't accidentally file at what-if version
Yes you can save your return with another name to test in. You can have many copies. Go up to File-Save As or Duplicate on Mac. Give it a name like add TEST to it. Your returns end in .tax2023 and should be in your Documents in a Turbo Tax folder.
There is also a What-If worksheet you can play with. Go to Forms Mode, click Forms in the upper right (left for Mac). Then click Open Forms box in the top of the column on the left. Open the US listing of forms and towards the bottom find the What-if worksheet. Or you can copy your file with another name and test in the copy. Go to FILE-SAVE AS.