Ok, this is actually a trick, because you can’t. The attribute on this field that allows it to be searched using the Advanced Find has been set to No.
I’m not sure how long it has been this way, but at least as far back as Dynamics CRM 2011. This is probably not a field that people use to search on, on a regular basis, so I am assuming this is why you don’t normally see it.
Here’s how you fix it:
1. Edit the Contact entity by going to: Settings, Customizations, Customize the System.
2. Expand the Contact entity.
3. Locate and edit the Do not allow Bulk E-mails of Contact field.
4. Set the Searchable property to Yes.
5. Click the Save and Close button on the toolbar.
6. Publish the Contact entity.
Now this field will be available to be searched using Advanced Find.
Note: We are doing this in preparation for some additional conversations we will be having shortly regarding Prospects and keeping your database clean and up to date.