For better viewport performance only 5% of the grass will be visible in the viewport. If you want to change that, select the ground object, go to particle properties >> grass >> Viewport Display and change the amount. The grass and the flowers will also appear as bounding boxes, if you want to change that, select the object you want to change in the grass and/or flowers collection in the outliner, go to Object Properties>>Viewport Display>>Display As and choose "Textured". Note that these changes will make your viewport much slower.