a cup of tea

‘Fancy a cuppa?’ is a very common British English phrase that means ‘Would you like a cup of tea?’

Fancy

Fancy means to feel or desire to do something.

For example

‘Do you fancy a drink?’ means ‘Would you like to go for a drink with me?’

‘What do you fancy eating?’ means ‘What would you like to eat?’

Cuppa

Cuppa is a British English word that means ‘a cup of tea’, though it can also mean coffee.

Another similar phrase is ‘Fancy a brew?’ which can mean tea, coffee and occasionally a beer!