=== Windows ===
Using PowerShell:
$home\AppData\Roaming\Bisq\
Using cmd:
%USERPROFILE%\AppData\Roaming\Bisq\
=== macOS ===
/Users//Library/Application Support/Bisq/
This folder could be hidden and not normally accessible on Macs, check the documentation by Apple to see how to be able to work with it.
=== Linux ===
/home//.local/share/Bisq/