If I don't want to use the date or time the picture was actually taken, can I use this software to stamp another time or date?
Yes. Using this software you can change the date and time of any picture that is in JPEG, TIFF, BMP and PNG file format. However you can only change the metadata of the files. You can't actually change the picture in any way. For a full list of features of the software, you can check the following official website.