Are all functions in the free version available?

All effects are in the free version available. Please define a selection for this. (Round buttons)
In the free version you can save in the flac, wav, m4a, aac and wma format.
Choose one of this formats in the filepicker.

Effects are gray

Please define a selection to apply the functions. (Round buttons upstairs of the curve)
See the tutorial at Define a selection

Can i read and write on a external SD-Card

Open a sound file from SD card is possible. For saveing on a SD-card klick on “Share” and choose a file explorer (like Total Commander) to set the desired location.

How is the lowest possible bitrate?

The minimal bitrate in Lexis Audio Editor is 96kb/s. If your record is in a lower bitrate LAE saves it anyway in this quality.

How do I save edited song to ringtone?

In the most devices there are a directory with the name “ringtone” on the first sdcard.
Save your sound file with LAE in this directory and choose in the Android settings under Sound and notifications/Ringtones this file.