Change adb permissions to rw? I have LineageOS on my phone. I'm looking to edit some files in /system.

I'm using root permission for adb devices from Developers Options. When I request to move file into /system, I get the message no permissions.

I tried to change permission with chmod but its not working. Since I don't have root permission for apps I can't change it from file manager either.
adb root then adb remount should be sufficient. However, you can also get addonsu for LineageOS of your version and device architecture, which enables root permissions for apps in Developer Options.

I understand some users might explicitly avoid opening up root for apps, so pick between the two according to your needs.