The SAT practice tests cannot be paused. However, both the mini-exams and the full-length practice tests give warnings about the time it will take before you start the section.
Be cautious of the time quoted before you start! Once you enter the section you will be given further warnings:
Please read this page carefully and notice that both types of exams give you warnings about the amount of time you have to complete the exam and warnings that you cannot come back to this section.
Please note: The practice exams state that you can take breaks between the sections. You will then be given a final warning that you cannot pause or retake the section later. Please consider these warnings before starting the timer.
For more information, check out this article: Can I reset my scores?