How to get the id if sending a media template via API?
The "id" is for the image using media ID, you will need to upload the media to WhatsApp to get the attachment ID first and send then media with ID. The attachment id can be used for a template or normal message.
1. You could upload the file to get the attachment ID with Stella
2. Or upload the file with WhatsApp API directly. Please refer to the below documentation for your reference:
If you would like to use the image URL, please use the "link" instead. However, it is not recommended for sending large media files.