The purpose of the Test of English as a Foreign Language (TOEFL) is to evaluate the English proficiency of people whose native language is not English. The test was initially developed to measure the English proficiency of international students wishing to study at colleges and universities in the United States and Canada, and this continues to be its primary function. However, a number of academic institutions in other countries, as well as certain independent organizations, agencies, and foreign governments, have also found the test scores useful. The TOEFL test is recommended for students at the eleventh-grade level or above.
Difference between Internet and Paper based Tests: TOEFL IBT measures reading, listening, speaking and writing skills and takes approximately 4½ hours. It is given on computer 30-40 times a year at test centers throughout the world.
TOEFL PBT measures listening, structure (grammar), reading and writing and takes approximately 3½ hours. It is given using paper and pencil 6 times a year at test centers where TOEFL IBT is not available.
Use of Internet-based testing (IBT)?
Internet-based testing makes it possible to capture and score test-taker speech in the most efficient, standardized, and objective manner. Internet-based testing will also make it possible to greatly increase the number of test centers, which is good for test takers.
Lectures and conversations in the Listening section are longer, but note-taking is allowed. In fact, note-taking is allowed throughout the entire test. The speech in the listening material sounds more natural and one lecture may use a British or Australian accent. Also, there are new questions that measure understanding of a speaker's attitude, degree of certainty, and purpose.
The new TOEFL differs is important ways from previous versions of the test -
It tests all four language skills that are important for effective communication:  Speaking, Listening, Reading and Writing.
It will be delivered via the Internet in secure test centers around the world
Some tasks require test takers to combine more than one skill.
Integrated questions or “tasks” in the new test help learners build confidence needed to communicate in the academic environments they plan to enter the new integrated tasks ask test takers to
Read, listen and then speak in response to a question.
Listen and then speak in response to a question.
Read, listen and then write in response to a question