This is not an OBS setting, or the setting of any streaming software. Instead, it depends on the streaming service you use, on the kind of contract between you and the service. The streaming service creates the different qualities.
To provide a range of qualities, the streaming service has to take your stream and create one additional stream for each of these qualities. Creating a stream of a different quality is called transcoding. Transcoding is somewhat expensive - you need CPU power for it, so it is usually not available for free. For Twitch, for example, you usually need to be partnered to be eligible for transcoding. And to get partnered status, you need some kind of reach - you have to have many viewers and regular streams. For other streaming services you may buy transcoding.
If you don't have transcoding, the stream you're sending from OBS is exactly the stream that reaches your viewers. If your screen resolution is too big for a viewer, or if you're sending with a bandwidth the viewers are not able to sustain as download, you're losing that viewer. So it is advisable to not stream with the highest resolution and with the highest bandwidth if you don't have transcoding. If you have transcoding, the viewer is able to choose the stream that suits his system best. But if you don't have it, he has to conform to your original stream.