I just found a bunch non-sensical notes on my iPhone which are apparently treatments for screenplay premises.  Here's a screenshot one I apparently wrote at 4am last September https://i.imgur.com/9l6Yhrc.jpg  (No idea why embed won't work)-  I think I was trying to write a lesbian rom-com. My favorite line is the bit that says: "doctor got #metooed" the meaning of which escapes me. But i love the possibilities.

Normally, I would never do any more planning than that (shorthand's into a Notes app or a one sentence premise in my brain) before opening writing software, which I'm not aying as a positive.

I wrote an actual treatment for a feature (I'm posing it on the WIP threat ATM) and it's made lots of things easier, so I'm curious everyone else planning. What do you do prior a first draft (and would anyone be brave enough to share a treatment - in exchange, I'll post more of my surreal Iphone note premises)
?  

I have an Excel spreadsheet for each feature, I have tabs for lots of things:

History before story
Details of the current world, rules, tech etc
Characters with full bios (sometimes I find photos of how I imagine them to look)
Plot, detailing all plot points both major and minor including B/C/D sub-plots
Scene synopsis - this puts each scene in order with a synopsis of what happens, I will split this to include the subplots so I can clearly see these away from the main plot but also how they link
Random notes tab