Ever CAD Tool has an option of Undo and Redo embedded in it.
This mainly helps in making changes when we make a mistake in a drawing file, sketch file, part file, assembly file or even when generating a drawing view.
Autodesk Inventor, has this option in a better way, by providing some additional memory when we work with large assembly files.
To enhance the Undo File Size:
Click on Tools > Application Options > Select the option show below
You can change the Undo File Size in terms of MB, you can increase this based on the assembly type and number of parts in the assembly.