Originally Answered: How do you get an office job?
Seek the assistance of a staffing company, temp-services or recruiter. You might want to start with your local State / county jobs ONESTOP (use a search engine and user that term, with your state, city, county to find the locations near you), who can help you with classes, to learn the skills needed for those jobs you are seeking. Some of the responsibilities disappeared in the 1950's-1980's, as technology replaced them.
Don't rely on online help wanted solicitations, as hundreds, if not thousands of better qualified applicants will apply. Those online systems are also geared to disqualify the vast majority, and whittle the list of qualified people to less than 10, from as many as 50,000 applicants. You really want to do your homework, learn who may be hiring, and get your resume walked in, by someone in the office, if possible, or through a qualified recruiter.
Don't use a recruiter that requires you to pay them for their services, unless you need help building a resume, and cutting through the red tape, after you've landed a few of these types of roles. You'll want to develop a functional resume that highlights your transferable skills, since you are seeking to enter a new career field. You might also consider a long-term volunteer role to learn some of the skills, and build experience before you decide to make the move. Work with your jobs ONESTOP, local college career counselors, for assistance and suggestions.
Local community colleges can be good resources, for training, advice and career assistance.