Trying to remove the existing flooring right up to the edge of the toilet may prove difficult if not impossible depending on what the material is.
How to remove a toilet to install flooring.
Wipe down the flange and surrounding area with a mixture of household bleach and water or use a disinfectant cleaning solution.
Before removing the toilet you will need to disconnect the water supply line drain all the water and remove two nuts.
If you are installing vinyl planks in a bathroom you may need to temporarily remove the toilet or you can install around it.
Remove the toilet tank.
This will allow you to remove the old flooring and properly reseat the toilet on top the new floor.
Installing new bathroom flooring requires removal of the toilet.
Unbolt the toilet from the floor.
Break the toilet seal.
If the subfloor is unlevel you can fix low spots with a self leveling product and sand or grind down high spots.
Remove the old wax ring.
Instead remove the pre existing vinyl flooring entirely if it is not level.
Toilets are manufactured with a wide range of toilet base footprints and the chances of finding a new toilet with the exact footprint are slim to none.
When reseating a toilet you will need a new wax ring which can be purchased from a hardware store.
Find the old wax ring that sticks the base of the toilet to the floor and remove it.
Do not try to sand down old vinyl flooring as it may contain asbestos.
Cover the drain hole.