Hi
Is there anywhere in the docs with what permissions for each folder the application should be. I’m running mine on a mac. It’s not my first Yii2 app, but I’ve changed environments and I’m noticing I’m having to put in my password to get anything to save in my editor.
Thanks 
Well, this is not really Yii related but to solve your problem you should make sure you are the owner of the files and have write permission 
For Yii, the following folders usually need write permission from the webserver:
@app/runtime
@app/web/assets
If you use apache you can tell it to run under your user (obviously this is valid for local devel environment).
Under apache dir there should be an envvars file
in this file you can set
export APACHE_RUN_USER=<your user>
export APACHE_RUN_GROUP=<your group>
In this way apache run as your user and group and you can own all the file without issue on webserver side. This will allow you to use also gii.
Otherwise CeBe suggestion is valid.
Thanks