Grafana Line Alert template

I’m using Line to send Alert but I don’t find where can I set the template
is it there any way I can change the template?

No, you can’t edit the template used for LINE notifications. Customisation of alert notifications is supported only for contact points that have an Option Settings section. You could however change the code and rebuild it, if you are conversant with Golang.
Related: Using custom message templates in LINE

Example: Telegram