Welcome @Paolo3 ,
If you define a mission that has any type of Waypoint Actions, then you must set the Path Mode (in Mission Settings) to Straight Lines. However, setting Path Mode to Straight Lines will cause the drone to stop at each waypoint to perform your desired actions.
You can design a mission to fly continuously by setting the Path Mode to Curved Lines, but none of the waypoint actions will be performed (because the drone never actually reaches the coordinates of the waypoint).
When using Curved Lines, you can set a photo interval (every ‘xx’ seconds or feet) and automatically take photos. You can also use the Photo button on the screen and manually take photos while the mission is running. Using Curves Lines is predominately used for shooting video, where you want smooth turns in the video.