If you click “Edit this Page” and “Upload it to the IF Archive,” it will take you to a page like this:
You can upload your file right there. IFDB does ask you to sign in, but, if you check the box to “Remember me on this computer,” you’ll only have to login one time, ever. Quick and easy.
If you really want to do it from the command line, you certainly can. No login required! (Please do update the email address below to your own, actual email address, so the IF Archive team knows how to contact you.)
curl \
-F file.1=@Murder_at_the_Manor.zip \
-F "name=Jkj Yuio" \
-F "email=you@example.com" \
-F $'filedesc=Murder at the Manor\n\nAuthor: Jkj Yuio' \
-F "rights=author" \
-F "directory=games/html" \
-F "tos=on" \
-F "tuid=qk7qwasgpawa90xu" \
https://upload.ifarchive.org/cgi-bin/upload.py