Open a new Google Form or a pre-existing one on your mobile web browser. Select the Responses tab underneath Untitled form; inside this tab, you can also toggle off Accepting responses.

Google Forms can be anonymous, but the form maker must enable that feature through the Settings tab.

The Google Forms web app will open in a new browser tab, displaying a blank form. Alternatively, you can start with a template, modifying it to suit your needs.

The form is available as a web form with its own unique URL. I bookmark that and keep it open in my mobile phone browser as well as a tab in Chrome or Firefox.