Are you talking about a Bachelor’s or undergraduate level? If yes, you want to get admitted into a school in which country? Different universities may have different procedures and requirements for admission.

First of all, for admission into a first degree level, you must complete your high school or equivalent level of education with good merits.

Depending upon a country you plan to go and university you intend to apply, the tests you have to take may be different. To prove your proficiency in English language, you may have to take IELTS or TOEFL test. Besides, if you plan to apply into any American university, you may be asked to take SAT or ACT test.

I suggest you to choose a university from the country you intend to go for your further studies. After that, go through the university website to find out their admission requirements and application process. Most universities usually mention all the information in detail.