Can you pray on clothes you sleep in?

There's no issue with praying in the clothes that you sleep in. Out of respect, out of adab for Allah, the salah would be valid. However, let's say you have an interview for example at work, you wouldn't wear the clothes that you sleep in to that interview, something important where you're speaking to somebody or meeting somebody. And our salah is speaking to Allah subhanahu wa ta'ala, so always try and change out of those clothes. Remember that often that outward appearance will have an impact on our heart in the salah as well, that we're preparing for that salah, we're really getting ready when we're doing wudu for example to remember that we are praying and talking to Allah, as we know from the hadith when we say, Allah responds and says that my slave has praised me. So really important that if you're able to, to change out of those clothes. If you're not, then the salah will still be valid, no issue with that.