Yes, you can delete the tax file by going into the "Turbo Tax" folder under your " Documents" folders.
However before that make sure you exit from Turbo Tax program. It may ask you to save the file which should be fine either way as you are going to delete the file anyway.
In the Turbo Tax folder you will see one or more turbo tax files with names ending in ".tax2018". If you just want to delete your own file, delete the ones with your name included in the filename. There may be .pdf version of the files that you may also want to delete. That should be it.
If you want to permanently erase the file from your computer, right click on the computer Recycle Bin and select Empty Recycle Bin.
Hope this clarifies the process.