Four serious options, one decision framework. The options are IELTS, TOEFL, PTE Academic, and the Duolingo English Test. The framework is simple: check what your target schools accept first, then pick the format that fits your brain. In that order. Picking a test before checking acceptance lists is how people end up retaking a different exam in a panic, and I've watched it happen more than once.
Start with the acceptance check. Pull up five to ten target programs and write down which tests each one accepts and the minimums. You can use an English proficiency requirement lookup tool or just read the program pages directly. Often the decision makes itself. Some programs only take IELTS and TOEFL. Some take all four. A few bury odd preferences in their FAQ pages that contradict the main admissions page.
Then the format question, and be honest with yourself here. Like talking to humans? IELTS speaking is a conversation. Hate that? PTE and TOEFL keep you and the examiner apart. Fast typist? Computer based tests reward you. Slow typist? Paper IELTS might quietly save you. Need a score this week? Duolingo and PTE deliver in about 48 hours. IELTS and TOEFL can take up to two weeks.
Logistics matter more than people admit. Test center availability in your city, dates that fit your timeline, and the question of how much IELTS score is required for USA universities versus the TOEFL they expect, all of it feeds the decision. A test you can sit next month beats a theoretically better test with no open slots.
Last thing: don't pick based on which test your friend found easy. Your friend is not you. Take one timed mock of your top two choices. The right test usually announces itself by section three. And if you want the diagnostic plus a plan built on it, that's exactly what the 8-week study plan at internationalstudyhelp.fyi starts with.