We say 'What time is it?' ( or 'What's the time?') if we know that the other person has a clock, phone, computer screen or other device to hand - that all they need to do is look at it. We say 'Do you have the time?' if you are not sure whether the person has any of the above to hand. The person might say 'No, I don't. I left my watch at home. But I guess it's about 8 o'clock.' Obviously, in other contexts, 'Do you have the time?' means 'Do you have the time (to spare to do something)?' - as in 'I'll help you' 'Do you have the time?' 'Yes, I've got plenty of time. I don't need to go into work until this afternoon.' Just curious..your profile says you're a native English speaker. Why are you asking this question?

What time is it? - This is a question you ask when you want to know the time of day. It can mean nothing else. Do you have the time? - This can mean two things, and it all depends on context. It can be used the same way as "What time is it". It can also be a question you ask when you want someone to spend time with you. You would usually ask someone this as a follow-up question if they offer to help you with something. Example: Person 1: We could really use some help getting ready for this event. Person 2: I would love to help you guys. Person 1: Great, we work on everything in the evenings. Do you have the time to help? Person 2: Of course! This is an odd use of the phrase, but hopefully it helps. Most people would use "Do you have the time" when they want to know the actual time of day, but it can be used in ways similar to what I showed. Thanks!