There is no entrance exam in TNEA. They consider 12th class marks.

In order to apply for TNEA counselling you must have nativity certificate and you must have 50% aggregate in 10+2 standard for other backward classes 40% is required.

To check complete eligibility criteria you can refer below link

https://engineering.careers360.com/articles/tnea-eligibility-criteria

For other state quota counselling is held seperately.

Good luck!!