All fire alarm panels require a lamp testing feature. If you can't find the information showing how to test the lamps in the operating manual, contact technical support for the manufacturer of the fire alarm panel. They will be happy to explain it.
The purpose of the lamp test is to catch problems with the lamps before there is a fire. In the olden days, before there were LED lamps, there were incandescent lamps. Incandescent lamps used a small wire (the filament) that got hot enough to produce light. It may take many years, but eventually all incandescent lamps burn out; their filaments burn out. Some will burn out sooner than others.
After a few years, because there are several lamps in a fire alarm panel, one or more lamps can easily burn out between times of annual servicing of the panel. When the firefighters arrive, if a lamp showing the zone of the fire is burned out, precious time is wasted looking all over the building. That's a problem.
To reduce the lamp-burnout problems, a button to light up all the lamps was installed in all fire alarm panels. That way, any lamps that were burned out could be found and replaced before there was a fire.
Nowadays, instead of incandescent lamps, LED lamps are used in all fire alarm panels. LED lamps are solid-state - there's no filament to burn out. I've never seen an LED lamp burned out in a fire alarm panel, and almost never seen an LED lamp burned out anywhere else. That doesn't mean that LED lamps won't burn out, it just means that LED lamps only burn out on rare occasions.
The Liquid Crystal Display (LCD Display) is a slightly different matter. I have seen where the display is misadjusted so it is hard to read, or where the display just didn't work anymore. That's a problem.
Just walking up to the panel and seeing the words "System Normal" does indicate that the LCD Display is mostly working. Seeing how well the LCD Display works beyond that depends on the manufacturer, and how much extra testing is included in the type acceptance testing that the manufacturer performed with places like UL, CE, FM, Etc.
The lamp test feature is still in all fire alarm panels. Sometimes, though, figuring out what buttons to press on a particular panel requires reading the operating manual, or even contacting technical support.