Usually, the number of simultaneous connections is around 5. However, some VPNs offer up to 10 connections (PureVPN) or even an unlimited number (Surfshark). Check our VPN reviews page with a comparison table.
Nevertheless, you can use a VPN router to route the whole traffic through a secure VPN tunnel for complete network protection.
In this situation, you will use only one available connection to cover all the devices connected to that router.