Handling log level and log format

**Question 1 - Log level**
In fluent bit there is an option to configure the log level using the "Log_Level" configuration
Documentation - https://docs.fluentbit.io/manual/administration/configuring-fluent-bit/configuration-file

I would like to see some examples/pointers on how to read the same in the output plugin
and perform logging appropriately.

**Question 2 - Logging format**
What should be the logging format used by the plugin? I see no option in fluent-bit to configure the logging format (plain text vs structured etc) at fluent bit level.

Thanks in advance