Copper and aluminium are the two metals used for the current-carrying conductor in a cable, and each has its place.
Copper has higher electrical conductivity, so a copper conductor carries the same current in a smaller cross-section. It is also stronger, more ductile, resists corrosion well and makes reliable terminations. These qualities make copper the standard choice for house and building wiring — for example APAR Anushakti HR-FR-LSH and Shakti FR-PVC wires use pure copper conductors.
Aluminium is much lighter and cheaper per unit of current, but less conductive, so an aluminium conductor must be larger to carry the same load. Its strength-to-weight advantage makes it the usual choice for larger feeders, service mains and overhead lines, where weight and cost dominate. APAR's AlumShakti multicore cables use aluminium conductors for such applications.
In short: choose copper for compactness, durability and most internal wiring; aluminium for large, cost- and weight-sensitive runs. The correct conductor size differs between the two for the same current, so always size to the metal you are using.