On Instagram, it is possible to shoot a video without having to keep your finger pressed on the shutter button.
Steps

Step 1. Open Instagram
It is the pink icon that represents a retro style camera.
- If prompted, enter your username and password, and then select Log in.

Step 2. Press the Home button
This is located in the lower left corner of the screen and will take you to your news feed.
When you log into Instagram, this is the page you are redirected to by default

Step 3. Choose Camera option
It is located at the top left.
You can also access this page by swiping right from your news feed

Step 4. Select Hands Free
This is the rightmost option below the button Capture.
In order for this option to appear, you may need to scroll through the different options below the shutter button

Step 5. Press the Capture button
Instagram will start filming as soon as you release the button. To stop filming, just press the shutter button again.
- In mode Normal, keep your finger pressed on the shutter release button throughout the recording.