Couldn’t you copy them into a reply, then delete the bits you don’t want to keep? I’m possibly misunderstanding though.
That’s one way of doing it.
Pro-tip on Android at least - if you open your Recents, you can manually select text that was on your screen even if it wasn’t selectable at full screen.
Is that an option on OneUi as well? I haven’t been able to figure it out.
I once had a keyboard app that also copied OTPs automatically, could’ve been GBoard, it doesn’t seem like a universal feature since SwiftKey doesn’t have it in my case.
Edit: I misunderstood your comment, most apps that I use that send out codes do log them in automatically if they’re open, so I have to manually copy a code only if I’m on a website.