Which file format is proper to save the scanned image?

Bitmap images can be saved in various file formats that fall into two categories - Uncompressed and Compressed. Uncompressed formats store bitmap images as stream of bits they were created (scanned, captured, drew, etc.), the actual file size therefore is the raw data size (pixel dimensions times color depth) plus rooms for extra pieces of information (file header, remarks, etc.). Common uncompressed image formats are BMP, PCX, PICT, TIFF, PSD, etc. These file formats are usually adapted for advanced publishing purpose because they keep the precise information of the original image, but they require much more disk space then compressed file formats do.

PICT & TIFF are best for resolution, but I would use JPG for resolution and size, and if possible, save at 99 per cent.

Depends on what you want to do with them. If you plan on editing them in an image editor, like Photoshop, then tiff is the most likely candidate. From there you can save it as a JPEG, or whatever.
Remember, if you want to edit it again, or might edit it again, do not save the master as a JPEG. That is a "lossy" image data format that gets poorer (loses data) every time it is altered and saved. Tiff is not lossy. PSD is Photoshop's format and it is basically tiff and is not lossy, either.

what image formats does the sony FIU 600/WIN fingerprint reader saves its image or what image format does it support/accept for its scanned images

which file format does the sony FIU 600/WIN fingerprint reader support

how do I edit scanned text?

I would save them as jpgs. They take very little space on your hard drive and storage.