Auto-complete contact list

If someone, unknown to me, sends me an email, his/her email address will automatically be added to my contact list.
I don’t want that or I want tpo have the choice to turn that off. How do I do that ?

That may be done by your email provider as eM Client does not have that ability.

What eM Client can do, is if you reply to a message, the address can be added to the Recipients History. But this is not a contact, just a separate list.

You can manage it in Menu > Settings > Mail > Compose > Recipients History. You can turn the feature off, remove unwanted address from the list, or add selected addresses to your contacts.

Thanks Gary, your answer came in my Spam-box. So I did not notice it earlier.
Have a nice day !!