When a player dies or resets their character, there will be a countdown until a player respawns. When a player respawns, they will appear fully healed on a spawn, which can be determined by a 
SpawnLocation. The player will receive a 
ForceField for a few seconds depending on the spawn's forcefield wait value that is edited in studio, before becoming normal and vulnerable depending on if the game allows them. Games may have the spawn point set to no forcefield via the Spawn point's values in Studio. When you respawn you appear, with a forcefield and the player is not vulnerable, but some games may have respawning disabled via scripts intentionally.
When you first put a spawn point in the Workspace, it will be with this decal. Although the decal is easy to modify via the Decal object that comes with the spawn point block.
Some spawn points might be team only, as if one for the blue team and one for the red team. This is easy to set up with the Teams folder in the Game (not workspace) and the TeamColor value in the spawnpoint. This was highly used in games around 2009 to 2019, although the actual last date of it being mostly used is unknown (so it might not be accurate).
Some examples of the usage of the Team Spawns are obby games, that change your team per stage so you spawn back on that point via team.