You can make WhatsApp always online on Android and iPhone by adjusting the screen timeout settings.For Android, go to Settings > Display > Screen Timeout and select 'Screen turns off automatically' and 'None'.For iPhone, go to Settings > General > Auto-lock and select 'Never'.You can also use screen timeout bypass apps or WhatsApp mod apps to achieve the same result.Alternatively, you can use the WhatsApp web version on a desktop web browser to stay online.