It’s just an informal chat. Nothing to be scared of. My recruiter simply asked me questions about my CV, education, country, what am I doing currently.
She seemed really happy about my Competitive Programming career. Apparently, they have seen that competitive programmers tend to better in the job compared to others. Making it to top 10 of ICPC regional boosts your chances of landing an interview with them.
Back then I still had around 8 months left till graduation. I asked if they were willing to wait for me and she said they would wait.
Apart from asking my basic question to me, she explained what their company does and what roles they have open. She also explained the interview process and types of questions I will be asked.
She then asks you when you are free for the technical round. She might ask you to give the technical round immediately after the HR round. If you are not prepared for the technical interview, politely decline and ask for time. The interview process is really fast so you probably will be getting around a week before they schedule the technical interview 1.