It is very easy to download any Reels video from Instagram
Let me tell you how to download Instagram reels without watermark.
Open the Instagram app and then select the video you want to download.
Click on the share button in front of that video
After that you have to click on add to your story below
After that you have to click on add to your story below
Click on the three dots appearing above that video
Now, this video will be saved in your phone immediately after you click on the save button