IELTS and PTE are two different English language tests. Both of these tests are used for immigration purposes only. IELTS stands for the International English Language Testing System, which has test scores ranging from a minimum of 4 to 9. The last one is the Pearson Test of English or PTE. It also has a score range, but the average score is around 80. It is not an official test.
The primary purpose of both these tests is to measure your ability to speak and understand the English language as it is taught in schools worldwide. In other words, they are standardized tests designed to determine whether you should receive a certificate proving that you passed an English course at school. IELTS tests are administered by Cambridge ESOL Ltd., Pearson VUE Inc., Worthy Professional Educators Ltd., etc. Pearson PLC conducts PTE examinations on behalf of the British Council.