By competitive exam what you mean is really important. If you mean competitive entrances then you can prepare for several entrances such as JEE Mains & Advanced, NEET, TS-EAMCET etc. If you are talking about scholarship examination then you can apply for KVPY (this are the options for the science students). Now if by competitive examinations you mean government job examination then you can give SSC MTS examination which has a eligibility for class 10 pass. Apart from this you can apply for NDA examination (if you have science) and in the age range 16.5-19.5 years then you can apply for NDA 2022 and you can also apply for State Government PSU's having eligibility of class 10 pass. So this can be some of the job options although I would recommend if you want to get good job posts in government services then you should carry on education atleast till graduation.

I hope this helps.