Hi @Lchaman, welcome to the community
Assuming you launch n8n with the tunnel parameter, your test and production webhooks should make use of the tunnel URL automatically.
For example using docker you could launch n8n with a tunnel using a command such as this:
docker run -it --rm --name n8n -p 5678:5678 -v ~/.n8n:/home/node/.n8n n8nio/n8n:0.209.3 n8n start --tunnel
Now when adding a webhook to your n8n workflow you can see both production and test URL would start with
https://$uniqueValue.hooks.n8n.cloud (which is an n8n tunnel subdomain):