If it is mounted to an underlayment, you may find it easier to just score it at the seams of the underlayment, and rip the underlayment up, with the vinyl still attached. I've done this when replacing flooring in some older homes. Much quicker to lay new underlayment, than to spend all that time and labor trying to scrape the vinyl off. You might consider going right over the old vinyl. Install a new underlayment (1/8 inch to 1/4 inch luan, for example), right on top. Use wood screws, and set them just slightly below flush with the surface. Then hit all the screw heads and seams with a very light coat of floor filler. If you're careful with it, you'll not even need to do any sanding. Finish it off by installing the new floor covering. Otherwise, you're going to be investing some time and elbow grease, hehehe... get a good, long handled floor scraper, and keep it sharp. Have Fun
You will need a 3 inch scrapper to start loosening the vinyl, whether it be sheet vinyl or tiles. Professionals use wider scrappers with a long handle, no bending. If the vinyl is stuck to wood use a heat gun to melt the adhesive and then scrape. If it is stuck to concrete heat should not be necessary. OR, if you really want to make an easy job of it buy dry ice and place it on the flooring. Wait a couple of minutes and the dry ice will freeze the adhesive. The flooring will pop up and little scrapping will be necessary.You can do this in small sections.
From a Ret. flooring installer If you want to install another floor, you dont need to remove it, you can simply go over it, but first lets talk prep work: A) Go to Home Depot, go into flooring section in back and find a large bag of Henry's flooring patch material. B) Take A small bucket and put about 1 cup of water to start with, and pour some patch in it, start mixing, you want the consistency of peanut butter, keep mixing up more but not too much water at first. C) Get a flat trowel, what you want to do is only skim the patch over the floor, no puddles, hold trowel at 90 degree angle slighly when doing this with the patch, after drying, scrape good with clean trowel to remove any humps or bumps You can now install any type floor over that, make sure it is smooth., and all crevices are filled in.
You didn t say if your on slab or wood.. If slab elbow grease and scraper along w/ a heat gum helps.. If you over wood the same method but check 1 thing. If the vinyl was put over a 1/4 inch sub floor normally called luan, get under that and pull luan and vinyl up all at once .. Much easier..GL
Before going any further, try to find out the age of the vinyl. Make absolutely certain it's safe to remove and does not contain asbestos.