"I would like to" is more formal than "I want to".

'I would like to' is more polite and more tentative than 'I want to'. As a request, 'I want to' can sound demanding, rude or childish, whereas 'I'd like to' is more polite. If you are expressing a wish or desire, 'I would like to' also suggests that this may not be possible to do.

“I want to”is always direct，but“I would like to”is euphemistic.