Most Helpful Girl
I'm not quite sure what you mean. If you're just looking for people to talk to, most people talk through replies on opinions first and then move to PMs. Sometimes, conversations start strictly through messages.
If you're talking about searching for profiles, you can go to your followers/following list if the user you're searching for is there. Otherwise, there is no specific search feature. You'll have to enter their username at the end of this URL link where the blank is if you know their username:
For example, mine would be: