Sign in with the bot's admin password (everything, including the settings) or its user password (using the bot without the admin settings).
Self-hostedThis bot
You set both in the bot's start command: -webif-pw for the admin password and -webif-pw-user for the user password (for example in your start script).
Official Docker containerThis bot
They are the container's environment variables PASSWORD_ADMIN and PASSWORD_USER (docker run -e … or docker-compose.yml).
Hosted bot (reseller license)This bot
Your hoster runs this bot. You find both passwords in your hoster's control panel for this bot.