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.