To make straight lines on an Instagram story, follow these steps: Open the Instagram app on your mobile device. Swipe right to access the camera and select the "Story" option at the bottom of the screen. Take a photo or video, or select one from your camera roll. Tap the drawing tool icon at the top of the screen. It looks like a pen or marker. Select the "straight line" tool from the bottom of the screen. It looks like a line with dots at either end. Choose the color and size of the line you want to draw. Tap and hold on the screen where you want the line to start, then drag your finger to where you want the line to end. Release your finger to finish drawing the straight line. You can adjust the line by tapping and dragging the endpoints or the midpoint to change the angle or length. Once you're finished, you can add text, stickers, or other effects to your story before sharing it with your followers.