You must have a neutral in order to make a pair of 120 volt circuits out of a 240 volt line.
If your main disconnect switch is at that location then a neutral will run from there down to your house panel which is now technically a subpanel. Just downstream of your main disconnect there you can wire in additional 120 and/or 240 volt lines and run them to subpanels in your various detached buildings, one feed -- 4 wire for 120/240 (hot, hot, neutral, ground) or 3 wire for 120 volt only (hot, neutral, ground) -- per building.
You may not run a feed from there to a patio or other location attached to your house given the one feed per building rule. Instead you must run the lines from the panel in your house.
Your city may require a special permit or a separate permit to do work upstream of your main disconnect switch. In addition you may need to have your power company (sometimes abbreviated POCO) disconnect your service during that part of your project.