Final answer:
The command for seeing prior versions of a document is ctrl + Z, known as the undo function, which reverses recent changes.
Step-by-step explanation:
The command that allows you to see prior versions of your document is ctrl + Z. This command is commonly known as the undo command. It lets you step back through the history of changes you've made to your document. If you accidentally delete something or make an unwanted change, pressing ctrl + Z will reverse the most recent action. If you need to redo something you've undone, ctrl + Y is typically the 'redo' command, while ctrl + S is used to save your document, and ctrl + P is used to print it.