When we start a conversation, especially at work or in a formal environment, we use an introductory phrase.
‘May I have a word with you?’
We use ‘I’d like to have a word with you’ or ‘can I have a word’ to politely say ‘I want to talk to you.’
‘Have you got a minute?’
We use ‘have you got a minute’ or ‘do you have a minute,’ to ask someone if they have time to speak now.
‘Can I see you for a minute?’ is also used to ask someone if they have time to talk.