You can use bluetooth, or Super Beam (play store app for direct wifi) or a USB cable, email, mms, all kinds of ways.
Just plug your USB cable into your phone and then into the PC. You would see it just like you would a flash drive or memory card. You can interact with it the same way and drag and drop files directly into the folder you want. The phone would be listed under My Computer or This PC or similar. The phone might ask you what you want to do when you plug it in, such as charge only, modem, mass storage, etc....choose mass storage.
OK - but now I want to upload into Quick Memo from the internal storage the files. There's an Import mechanism, but it doesn't seem to be connected to Internal Storage......
Because Google Docs can open docs and Google Sheets can open Excel files. Quick memo is basically just a proprietary format with LG.