Your question is difficult to answer because it is ambiguous and conflates several ideas. I'll try to take them one by one.
Does being in space change anything regarding time?
No. There is nothing special about space itself that changes the perception of time. Even the word space is ill-defined, but it usually means "outside of Earth's atmosphere", that is, if you go up far enough, you'll end up there. An altitude of 100km is commonly accepted.
Therefore, if we define an astronaut simply as someone who goes into space, then obviously that won't change anything to their perception of time.
Can time pass faster or slower for yourself?
No. From your perspective, the rate at which time passes never changes. If you have a working clock with you, nothing you can do will alter the speed of the second hand.
Can time pass faster or slower for yourself compared to somebody else?
Yes. It is possible for two people with identical clocks to meet again at a later time and see a difference in what the clocks indicate. This can happen even though neither individual ever saw a change in how fast the second hand moves.
This phenomenon is called time dilation. It happens when there is a difference in either velocity ("speed") or gravity. If I go faster than you, or if I am on a planet that has greater gravity than yours, then when we meet again, my clock will show a time earlier than yours.
This will happen even though both of us felt the time pass at the same rate. It's only when we compare our clocks that we'll notice a difference.
Does this affect astronauts at all then?
Sure. It will affect anything that moves at a different speed or experiences a different gravitational field. In the the case of an astronaut, they're probably in orbit, and so are going very fast. Therefore, their clock would show a time earlier than yours when they come back down on Earth.
But they're also at a higher altitude, and so will experience less gravity than you who is standing on Earth (about 90% on the ISS). Less gravity means that their clock would show a time later than yours when they come back.
The effects are opposite, but not equal. The net result is that after 6 months on the ISS, the astronaut's clock would be about 0.005 seconds earlier than a clock on earth.
Does that mean they age less than people on Earth?
Indeed. If we're both 30 years old and I hop on a very fast ship, I might come back after 50 years have passed on Earth, but only one year has passed for me. I will have aged less than you.
Does that mean they live longer?
This is the ambiguous part and it is more of a language issue.
No, in the sense that if we were born at the same time and we both died at 80, we will both have lived the exact same time. If we had counted every second since our birth, we would end up with the same number. We both experienced the same amount of time even though we didn't die at the same time.
Yes, in the sense that after we reunited on Earth, I would die 50 years after you did. I would have been able to see things you couldn't. But once I die at 80, my second count will be the same as yours.