In 2023, The median salary for a systems administrator in the us is $80,000 per year in the US. The salary can go significally higher with top companies like AT&T, NVIDIA, Boeing ,Apple and more paying upto 180K per year. With that in mind, getting microsoft azure certification can be a big turning point in your resume and technical knowldge.
Typically microsoft certifications are valid for 12 months , however in the real world employer will keep holding value for your certificaiton at least for 2-3 years and more unless microsoft changes the certification. For example in the past before the AZ-104 exam there was the AZ-103 exam before. but for the next couple of years microsoft will stay with the AZ-104 as its leading entry level certification.
After you finish studing and did some practice tests , go to microsoft offical az-104 page. there you can schedule your exam. You can take the exam at a test center close to you, microsoft has a search where you can find test centers close to your location. Another option is to do online , but keep in mind they have a lot of restrictions for you to be eligible to do the test online.
If you already had the old microsoft certifications such as MCSA or MCSE windows server 2016 , then this certifiation replaces those.