If you want to see it where? If you want a string you've got a string. If you want to write text to something resembling file I/O (e.g. stdout) then std::print and std::println are what you need instead of std::format
Stroustrup's I/O Streams is a weird dead-end C++ technology. Bjarne is probably never going to get over it, but everybody else should forget about it ASAP.
Worth pointing out that the iostreams library is the work of many hands, so Stroustrup is not solely to blame. I just found this old SO question which I answered many years ago (I am anon/Neil) which addresses this:
Stroustrup's I/O Streams is a weird dead-end C++ technology. Bjarne is probably never going to get over it, but everybody else should forget about it ASAP.