Again, not the greatest idea. That's actually less safe than using a book and writing it down. Hackers take remote control of systems all the time, and if they find the file...... at the very least I'd ensure the file is password protected. Encrypted too.
My band has an account and password, but you can't access the account - even with that - without also generating a dynamic password which has a lifespan of 15 minutes. That dynamic password is generated on my phone by entering a 6 number password.
A tip for people having trouble creating passwords..... we tend to try to think of words, names, or places. Instead, try using patterns. So for example, a password for Youtube might be the number 7. Looking at your keyboard, a number seven could be made up of yuijn. Hope that makes sense.
There are tools, as have been mentioned earlier. Passwords are a pain.
Also, full disclosure - it's all a matter of what's bearable to you. For example, my computer (Windows) does not have a password. I took it off. I couldn't stand not having access to the computer whenever I needed it, and the password was an extra step (I never turn my computer off). I know the risk, I accept it. My wife also knows all of my password to various sites as a "backup". She's free to log in any time she wants. It's not ideal - far from it - but it works for me.