I visited Georgia last year on valid UK 5 years visa on Pakistani passport without any Georgian visa, also the immigration Georgia sent me a link which was really helpful.
If you have a valid visa/residence permit from UK,USA,canada,new Zealand, Australia, any EU country or residence permit in Saudi Arabia,Oman,Qatar,Bahrain,Kuwait,Uae you may enter Georgia without a visa for 90 days.
However if you do not meet the above requirement, you will need a Georgia visa on Pakistani passport and Embassy of Georgia in Tehran can entertain your visa application. Moreover a invitation from Georgia is a must for Pakistani passport.
Here you can find all your answer from this website.