Add a specified actor to the current level, how to programmatically implement this functionality.Can you give me some ideas?
From what I get you wish to spawn an actor from C++. In that case:
Example code:
ATextRenderActor* text = GetWorld()->SpawnActor<ATextRenderActor>(spawnLocation, spawnRotation);
Can do it anywhere you have access to GetWorld() … PlayerController, any Actor, GameMode, etc.