PlayStation users are able to use voice chat with each other through PlayStation's ‘Party’ system, which includes voice and text communication. More information about the PlayStation Party system can be found in this ‘Parties’ article located on the PlayStation support site. PSN Parties and EVE: Valkyrie squads are totally separate systems which when used in conjunction with each-other provide the best possible experience for EVE: Valkyrie players on PlayStation VR.
In-game, players are able to invite friends, recent players, and/or PlayStation Party Members to their squad.
When a player receives an invite, a sound will play. The player will need to hit the PS button to see their invite in their notifications, as nothing is shown visually on PSVR for system notifications.
An EVE: Valkyrie squad invite looks like this: