To send a video message on WhatsApp, you have a couple of options depending on whether you want to send a pre-recorded video or an instant video note (a short video recorded directly in the chat):

Sending an Instant Video Message (Video Note)

1. Open the chat where you want to send the video message.
2. On Android, tap the microphone icon next to the text input field to switch it to a video camera icon. On iPhone, the camera icon is already next to the text field.
3. Press and hold the video camera icon (Android) or the camera icon (iPhone) to start recording your video message. The recording can last up to 60 seconds.
4. While recording, you can switch between front and back cameras.
5. To record hands-free, slide your finger up to lock the recording and then release your finger.
6. When finished, release the hold or tap the send button if using lock mode. The video message will be sent automatically.
7. You can cancel the recording by sliding left or tapping cancel before sending

Sending a Pre-recorded Video

1. Open the chat where you want to send the video.
2. Tap the attach icon (paperclip) or camera icon.
3. To send an existing video, select "Gallery" or "Photos & Videos" and choose the video you want to send.
4. Add a caption if you like, then tap send.
5. WhatsApp supports sending videos up to 100MB in size with a resolution up to 720p (depending on connection speed)

Additional Notes

• Video notes are private and cannot be forwarded by recipients.
• You can reply to a received video note by pressing and holding the camera icon again.
• Video notes auto-play muted previews and can be played fully by tapping them in chat

This method works similarly on both Android and iOS devices. For more visual guidance, there are tutorial videos available online demonstrating the process step-by-step