1. Download and share Reel from Instagram
If you liked a reel and you want to share it on Whatsapp, then it has to be downloaded first.

Steps:
Open the Instagram and choose the Reel you want to share.
Tap on three dots (⋮) and select “Copy Link” option.
Use an website or app to download
SaveFromNet (https://en.savefrom.net/)
Instasave (https://instasave.io/)
Or download any Instagram Video Downloader app from Play Store.
After downloading, open Whatsapp and send videos to that person or group.

2. Share direct link
If you do not want to download, you can also share the link of Reel.

Steps:
Open the Instagram app.
Open the reel you want to share.
Tap on three dots (⋮) and select “Copy Link” option.
Now open Whatsapp, go to chat and paste the link and send it.

3. Share from Instagram on WhatsApp directly
Instagram also gives you the option to share reel directly on Whatsapp.

Steps:
Open Instagram and open your favorite Reel.
Click on the share icon (➦).
Tap on the Whatsapp icon visible below.
Whatsapp will open, now choose the name of whom you want to send and send it.