Because you lack a Steam library connection, you must use external tools to download from the Steam Workshop.
Some mods may not work on a cracked version if they require a specialized mod loader, though most work fine. EID/Scripting Mods: how to install mods the binding of isaac repentance cracked
You must have defeated Mom (at the end of Depths II) at least once on your save file for mods to work without disabling achievements/progress. Troubleshooting Common Issues Because you lack a Steam library connection, you
Some mods require "Repentogon" or specific script extenders that may not play nicely with cracked copies. Stick to standard Lua-based mods for the best results. and the mods should be active.
Launch The Binding of Isaac: Repentance, and the mods should be active.