I am from Tamilnadu, India. We don't have a common family name as last name. And our names mostly have single word.
Here children add their father's name as last name. And women once get married will have their husband's name as last name.
My name is Kumaran and my father's name is Rajendhiran. So, my full name is Kumaran Rajendhiran.
This case isn’t that uncommon! Worldwide, two of the most common naming conventions are:
1. Given name + group descriptor (profession, locality, tribe, etc. such as Jim Baker or Joan Rivers)
2. Given name + parent’s given name and gender (such as Dwayne Johnson or Jóhanna Sigurðardóttir)
Iceland is especially fun, as they not only append a parentage name, but alongside -son and -dottir they’ve introduced a gender neutral suffix (-bur), and they don’t want you to make up first names out of the blue!
“[Iceland’s] Personal Names Committee maintains an official register of approved Icelandic given names and governs the introduction of new given names into Icelandic culture.” — https://en.wikipedia.org/wiki/Icelandic_Naming_Committee
One word names are called “mononyms”. Your example is again an example. You may have others around you with the same name but write it as Kumaran R (the initial derived from the first letter of the father’s name or the place of origin). Some may not even use an initial. These naming schemes, which are as valid as any other on the planet, have already caused a lot of trouble for people with PAN cards and Aadhaar (I recommend you read up on those if you aren’t aware).
