is there any way to send an email template using the sendwithus service? I searched a lot but nothing found.
The documentation is poor.
Any code example? I am using PHP
You can find the SendWithUs templating documentation here: https://www.sendwithus.com/docs/templating. It explains both the API calls and the formatting you need to use to replace aspects of your templates, which you store inside SendWithUs.
However, you're using PHP and they've created a library just for you to use that also helps with the templating side of things.