For My personal and private miscellanous thoughts i have been writing on a diary, but i always need to have it with me and (im kinda ashamed) i dont write good if i write as fast as on computer. I obviously cant copy/paste and i use a pen. I also find myself better with a keyboard so using a computer is what i think the most efficent way. Now, my daily driver (and what im writing this on) is a MacBookAir 2013 11" with (still) MacOS 10.14.5 installed and to write I’d use LibreOffice (duh). I know thou that this isnt private, its connected to the internet and its still using MacOS. I know a bit about technology (i find it weird for someone with zero knowledge of it having even found lemmy, but who knows), but i am certanly no expert. That’s why i am asking you how could i write on a computer privately. Nothing needs to get online but i will need to atleast have other documents or documents itself come in trough a USB probably. I am certain i need to install a Linux distro or a BSD. Keep in mind that if i need that machine not on the internet id need to have another machine wich is and from this machine would probably need to get stuff out and into the “private one” with a USB. This is probably confusing and if it isnt relative to the sub and needs to be deleted, please warn me with a comment so i can copy and save this post to post it somwhere else before it gets deleted.
Depends on your threat model and what you’re intending to guard against. You’re running an unsupported version of macOS so we’ll address that first, if you don’t mind losing 32-bit app support I would consider upgrading to Catalina at least. 10.14 Mojave stopped receiving security updates in 2021.
If you’re worried about someone physically getting your laptop I would enable FileVault in System Preferences with a strong password (you can enable it for the boot drive and also removable drives like USB sticks), and make sure you shut the laptop down whenever you’re leaving it somewhere.
TextEdit can work for writing simple documents but LibreOffice is a good option too, but the macOS port isn’t very good (lots of bugs and it runs slow af for me but YMMV)