Phone tips (if you cannot see “Upload / +”):
1) Open the folder and make sure you are signed in to Google Drive (best: open in the Google Drive app).
2) If you cannot create a new folder, that is normal. Just use “Upload / +” and upload your file directly into the folder.
3) If you are in Facebook/Instagram browser, tap menu → Open in browser.
4) If “Upload” is still missing, you likely do not have upload access. Please contact admin.