hi,

you may appear in polytechnic entrance test after you have completed class 10th or 12th. from the month of january many state wise polytechnic entrance test form will release. for utter pradesh polytechnic entrance test form will release on january 1, 2020 tentatively. you may follow the below link to know more details,

https://engineering.careers360.com/articles/jeecup

if you want to know  about any other exam you may mention in comment section.