One can only get permanent residence permit only if they are married to a Malawian.it takes less than 4 months to get it and one has to go to the immigration offices to push for the files to be processed.it's best to do it from Lilongwe.otherwise other permits issued to foreigners are temporary residency permit,work permit and the business permit.There is no quickest may ,per se,just submit your complete application,and push the officer.they are friendly people.hope this helps.