Since the 10/03/16 update, players can edit a very short profile to tell more about themselves to other.
This profile is readable by every other player. It is meant to give informations about what the player likes, where he/she is from and what languages he/she speaks. You can specify which country you are from and write a very short biography (limited to approximately 120 characters).
Obviously, this profile is entirely optional. However, most player do read it, so it can ease your contacts and help you find people who are susceptible to share interests with you. It's also helpful as it can promote respect of tastes, opinion and help with relations player courtesy.
How to edit a profile ?
To edit your profile, you have to click your character.
A window will open, in which you will find a picture of your avatar. In the top-right corner, you can choose your country of origin by clicking the flag (by default, it is set on "MnF Flag"). The text area is just below. The changes are live immediatly, so don't worry about the absence of any "save" button.
How to see other players profile ?
You can see the other players profile by clicking their avatar. It will be displayed exactly in the same places than yours is, meaning in the top right corner of the window.