YES, you must write the phase 1 and 2 of HITSEEE to complete the exam.

further, since you're a HITSEEE aspirant, below are some of the best tips and strategies that you can follow to ace yoru HITSEEE Exam :

1. Understand the Syllabus.
2. Make a Time-table.
3. Refer to Online Notes and HITSEEE Study Material.
4. Practice HITSEEE Previous Years' Question Papers/ Mock Tests/ Sample Papers.
5. Revise the chapters.
6. Rest.

Further, to know more about the HITSEEE Exam, then you can follow the below mentioned link to know more about it : https://news.careers360.com/hitseee-2022-exam-date-for-phase-1-and-2-released-at-hindustanunivacin

I hope that this will help.