Onto or on to?
The preposition onto meaning ‘to a position on the surface of’ has been widely written as one word (instead of on to) since the early 18th century, as in the following sentences:
He threw his plate onto the floor.
The band climbed onto the stage.
In US English, onto is the regular form, although it isn't yet fully accepted in British English. Nevertheless, it's important to keep a distinction between the preposition onto and the use of the adverb on followed by the preposition to (meaning ‘onward and toward’). For example:
√ Let’s move on to the next point.
X Let’s move onto the next point.
√ Those who qualify can go on to college.
X Those who qualify can go onto college.