I could not figure out how to clear Pydroid's terminal history.
I tried hictory -c and history -d and history -w and that does not work. Clear and cls are not available commands.
I figured where the history is stored in a file. The following commands worked for me. You must restart Pydroid to see the change.
/storage/emulated/0 $ cd ~
~/data/ru.iiec.pydroid3/app_HOME $ ls -a
. .. .ash_history
~/data/ru.iiec.pydroid3/app_HOME $ rm .ash_history
~/data/ru.iiec.pydroid3/app_HOME $