The ACT test is a Standardized test used for college admissions in the united states it is currently Administrated by Act, A non profit Organization of the same name. The Act Test covers four academic skill areas: English, mathematics, reading and scientific reasoning It also offers an Optional Writing Test

The Egyptian scholastic test (EST) is an entrance exam used by Egyptian colleges and universities to measure the students knowledge and skills ( for those students in the American Educational system (only in Egypt). The first test was heled in October 2020. The Egyptian scholastic test (EST) is inspired by SAT. The test was made after the continuous leaking for SAT worldwide. According to the Egyptian minster of education, he announced EST exam to guarantee fairness between the Egyptian students to enroll in universities and colleges.

The Act test is recognized internationally while Est isn’t there’s a difference in test times and grading systems for example:
The highest grade in an Act exam is 36
While it’s 1600 in Est
Another difference is the science section in act its similar to a reading passage while in est it actually has a curriculum and should be studied independently

In ACT You’re given a point for every question you get right (there’s no penalty or point deduction for wrong answers). The total number of questions you get right on each test (English, Math, Reading, and Science) equals your raw score . Your raw score for each test is then converted into a scale score (1–36)
The EST is based on a 1600-point scale, with 2 sections—Math and Evidence-Based Reading and Writing—scored between 200 and 800. There is also an optional essay, which is evaluated separately. There is no penalty for wrong answers, so your raw score is the sum of the number of questions you answer correctly.

Each major has its own website which you can use to reserve
https://my.act.org/account/signin
https://egypt.estests.com/

It depends on your situation, if you’re planning in traveling abroad then taking Act is preferred because its recognized internationally unlike EST but if you’re staying in Egypt EST is better