Hi Oumayma,
There are a few ways I can think of to accomplish this, and it's up to you how you'd like to move forward. I believe you'd be able to set up a signature option for the field if it isn't already configured for one. Then all you would have to do is remove access from security groups that should not see it. Another thought is that you can use Conditional UI. Conditional UI can be more difficult for security groups in the long run, but it is possible to accomplish. They also tend to put a little more strain on the DB. Finally, you could create a duplicate application that doesn't have the insert. Again, this could then be controlled through signature options. This option feels like the most extreme scenario, but would get the job done.
You might even be able to get into Global Data Restrictions, but that is similar with Conditional UI. You'd always have to remember to add to it if you create a new security group that should not have access.
Thank you,
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Allan Henle
Naviam
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