What does toner for bleached hair actually do ?

I bleached my hair so as you can guess its orange yellow and blonde, then a woman told me to buy a toner for bleached hair so i did and i have it, but what does it do exactly ?What does toner for bleached hair actually do ?
When you use a toner on your bleached hair, it helps get rid of any yellow or orange that is in your hair. It doesn't completely get rid of the tones, but does help a lot. Most people have to bleach twice and then tone to get the light blonde. But three processes is a lot for your hair to go through. Maybe use the toner and then in about a month (if you can live with your hair looking however it turns out after the toner) bleach it one more time, but leave it on for a shorter amount of time.What does toner for bleached hair actually do ?
Its just like hair dye it tones down the yellow and brassy tones of your bleached hair, IF you would have bleached it correctly it wouldnt have turned yellow or orange this is should never be done at home cause bleach is very bad for yor hair and can cause it to break and become fried
it supposedly takes the brassiness out. the orange yellow for example and itd tone it down to a blonder color not orange.