Infill stores profile facts and extension settings in browser extension storage. This data is used to suggest and fill form fields when you choose to use the extension.

By default, profile data stays local to your browser. Infill does not sell personal data.

If you enable optional encrypted profile sync, encrypted profile data may be sent to Infill's backend so it can sync between your devices. A passphrase is required for encrypted sync. Do not enable sync if you do not want encrypted profile data sent to the sync service.

The extension may access the active tab to scan forms and fill approved fields. Form data is used only to provide the requested form-filling functionality.

more on: https://useinfill.com/privacy