How to work with Extrafields

Using my Dolibarr PM modules
1

Hello to everyone,
I am using version 15.0.2 plus multi company and I would like to know how to show the extrafields only when these are populated, when I use the function “send email”.

Is there anyone who can help me with this trick?

Many thanks in advance.
GM

2

many thanks to Jade, solved with a default db!