Thank you for your query and the private messages. I am repeating some information given to you for the benefit of other bloggers.
Though PhD is research based, it can be pursued either on a full-time or part-time basis (as well as by distance learning mode). Please see various links at https://www.google.co.uk/search?q=ph...sm=93&ie=UTF-8
Also kindly see the links at https://www.google.co.uk/search?q=ph...tance+learning about PhD by distance learning.
You can join an academic institution; but you may not get the wages that you are getting now, as you may have to start as a fresher. Unless we know what you would like to do and what your interests are, it is difficult to advise you.