A forex VPS is a small always-on Windows server that keeps MetaTrader 5 running when your own computer is asleep. For copy trading it matters twice over: trades are only mirrored while the terminal is connected, and a VPS near the broker's server reduces execution latency.
For a single MT5 terminal running the Aurex copier, 2 vCPU, 4 GB RAM and an SSD is comfortable. Choose a data centre close to your broker's servers rather than close to you.