How to make a suggestion?

Curious as to how to make a suggestion.

If you hit home twice (to get to your "Search iPhone) it does not find a phone number in your contact list. It will if you type the name, just not the number.

However if you go to Phone > Keypad and type in a number and it happens to be in your contact list, it will tell you the contact.

I would like to see the same ability in the "Search iPhone" and wanted to know where to suggest that.

Thank you in advance.