You may not want to hear this, but if you are with a person who refuses to talk about the future, then there is a good chance you are with a person who does not see a future with you. It will not do any good to push them to talk about it; in fact that may make them more distant.
However, talking about the future is vitally important for a long-term relationship. Every person has their own ideas about what they want, whether it is: Jobs, vacations, personal time together, or even the house they want to live in. But it’s not just that. The language you use, and your tone, can convey a lot. I coached a couple who got into a lively conversation about the house each wanted to live in. I had to stop myself from laughing, because they were each describing the same house, but they were not listening to each other, so their conversation kept getting more heated until I had each of them take turns. So, don’t just talk about the future, listen to what your partner is saying. They may want exactly the same thing, but they could just be using different words.