The federal government of the US has around 100,000 vacancies per annum. This is a lot of jobs and due to the sheer numbers involved, many of them remain unfulfilled. Apart from that, many qualified Americans also think that the application criteria are too hard for them to even bother to apply for a federal job.
However, the process is neither complicated nor overly difficult. On the contrary, it is easy enough to apply, if you understand the process.
The one problem with applying for such a federal job is the extended waiting period.  Since there are so many vacancies and all of the applications must be properly vetted before onward processing, the waiting period between application and securing a job can stretch up to 20 months.
Yes, it is a long waiting period, but it is certainly worth your time and effort. This is because of the host of benefits that come as part of the package with a permanent federal job. These include paid access to healthcare, vacations, life insurance, training, sick leaves, post-retirement pensions, and many other benefits.
With that said, you should always remember that not every candidate is suitable for every job. For example, if you decide to apply for the post of director NSA and you are an 18 year old fresh out of high school, your application will inevitably be rejected. The point to remember here is that you should only apply for a job whose criteria meets your aptitude and qualification.
Federal government jobs are typically divided into three main categories:

The Competitive Service

The competitive service has the largest number of federal jobs. This makes it the single most popular option whenever anyone wants to apply for a government job.

The Excepted Service

 The ‘excepted services’ are different from the more traditional jobs available with the federal US government. Here, many candidates are often directly recruited instead of applying on their own. These include intelligence agencies and other sensitive work involving national security.

The Senior Executive Service (SES) 

The SES is characterized by the senior-most levels of the American government. The eligibility criteria may be extremely strict but the rewards are worth it since there are only 8000 employees in this cadre and they enjoy perks and privileges commensurate with their position.

Applying for Federal Government Jobs

There are many different ways through which you can apply for a career-defining job in the federal government. As a general rule, you will have to apply via the relevant portal. For example, the US postal service has its own online job portal.
If you are selected, you will have to appear for an exam and after passing that, you will be subjected to different medical tests and background checks. Once the process is complete, you will be recruited for your desired position.

Conclusion

While it is true that getting selected for a federal job is not very easy, once you have been selected, you can look forward to a lifelong career.