Numerically... the AFQT score of 79 means that you scored higher than 79% of the people in the control group that is meant to represent the average person.
The AFQT score is ONLY USED to determine your ability to join a particular branch and has nothing to do with being qualified or not for specific jobs in the military.
USAF and USN require a 50+ AFQT
USCG requires a 45+ AFQT
USMC requires 32+ AFQT
US Army requires a 31+ AFQT score.
These are the absolute minimums they are allowed to accept.
The reality is that the recruiters can set higher standards and realistically, no one is going to bother looking at you right now unless you are 50+.
A 79 is a good score.
And while the AFQT is not used to determine job qualifications, it is derived from the other scores which are. so to score high here, you will likely also have high scores in the tests that are used to determine qualifications (or used to derive the scores used to determine qualifications) So the odds are good you will qualify for a good number of different jobs.
Aside from the AFQT, there are 10 separate scores derived from the 9 individual test portions of the ASVAB. (the 10th score is a combined score of two others)
You are thinking about the Navy or Air Force.....
The Navy (and the Coast Guard) uses these individual scores DIRECTLY. You can look up and find the ASVAB requirements for each rating (Navy job).
For example, to be an DC (Damage Controlman) in the Navy requires:
MC (Mechanical Comprehension) and AS (Automotive and Shop Information)
Are scores derived dirtectly from your subtests.
VE (Verbal Expression) is found by adding your Word Knowledge (WK) and Paragraph Comprehension (PC) scores together. Both WK and PC are also direct scores from the subtests.
Your three scores added together must be 158 or higher.
The Air Force uses these scores combined together in different ways and combinations to create four specific "Composite scores" known by their acronym, M.A.G.E.
When you look up an Air Force AFCS (Air force job code) it will give you the MAGE score requirements.
(Marines and Army also use their own versions of "composite scoring" as well)
For example, to be an AFSC of 1A231 (Aircraft Loadmaster)
You need a G(General) score of 57.
The (G)eneral composite score is derived from the ASVAB scores of Verbal Expression (WK plus PC) and Arithmetic Reasoning (AR) and adding them together.