Many companies specify the need for a certification in job postings simply to weed out unqualified candidates as quickly as possible. The reality is that for most companies, real world experience and demonstrated success will count more than a certification.
For a long term career path with few limitations a much better choice is to obtain a B.S. in Computer Science, or an advanced degree, from a school with a renowned reputation. These degrees demonstrate that a candidate can absorb abstract ideas, apply them to new situations, and have the discipline to succeed.
However, certifications in limited subjects have their uses when evaluating candidates that haven’t had the opportunity to be admitted and graduate from schools offering computer science programs.
Amazon currently offers ten different certifications. The graphic from Amazon’s certification page (https://aws.amazon.com/certification/) provides the names of the certifications, how they are categorized, and the recommended experience associated with each of the certifications.
Note that to obtain some of these certifications, Amazon requires individuals to have already obtained a prerequisite certification. For example, to obtain a Professional Solutions Architect certification, the Associate Solutions Architect certification is a prerequisite. For any of the specialty certificates, both a Foundational Cloud Practitioner and one of the Associate certifications are needed as a prerequisite.
In my opinion, most technical people interested in obtaining an Amazon certificate should start with the Associate Solution Architect. This demonstrates more advanced knowledge than the Foundational Cloud Practitioner and serves as a good prerequisite for later advancement or specialization.
To prepare for taking a certification exam there are many options. Amazon itself offers seven on-demand Exam Readiness courses available at no cost. This is a great choice for people that have the self-discipline to learn without an instructor at their own pace.
For people that need a more structured learning environment there are a variety of online courses from various training vendors including Udemy, Cloud Academy, Lynda.com, and many others. In addition, many community colleges and adult education programs around the country offer traditional classroom courses to prepare to take the AWS certification exams.