Follow to below steps:
Step 1: Open Instagram Profile
Copy any user Instagram profile and click on IGTV.
Step 2: Open IGTV Video:
Click on any IGT Video
Step 3: Copy IGTV Video Link:
Copy selected IGTV Video link. Example: https://www.instagram.com/tv/CKgSnunnOf3/
Step 4: Paste Copied Link
Paste the copied link and click on Download Now button
Step 5: Download IGTV Video
Download on the Download button to download IGTV video.