How large is the area covered by coordinates XX°YY'ZZ"N/XX°YY'ZZ"E?
This is a coordinate, a single point. No area or distance can be calculated from that, sorry ...

https://en.wikipedia.org/wiki/Geographic_coordinate_system

The length of one arcsecond depends on the latitude. The Wikipedia article explains it quite well. Distances between two coordinates can be calculated via the great circle distance. Calculating areas on earth's surface is more involved, since they require a projection into 2D.