diff --git a/sea_transport/system/apparatus.h b/sea_transport/system/apparatus.h
index ff628e8..7464395 100644
--- a/sea_transport/system/apparatus.h
+++ b/sea_transport/system/apparatus.h
@@ -12,28 +12,85 @@
 #include <QDataStream>
 
 
+/**
+ * @brief Main system class
+ * 
+ */
 class apparatus {
 private:
+    //! Static pointer instance
     static apparatus *_instance;
+    //! Static path to save file
     static const QString filename;
 
+    //! Pointer to users subsystem 
     auth_system* _auth_system;
+    //! Pointer to objects subsystem
     object_system* _object_system;
 
 public:
+    /**
+     * @brief Construct a new apparatus object
+     * 
+     */
     explicit apparatus();
+    /**
+     * @brief Destroy the apparatus object
+     * 
+     */
     ~apparatus();
 
+    /**
+     * @brief Get the auth subsystem object
+     * 
+     * @return auth_system* 
+     */
     auth_system* get_auth_subsystem();
+    /**
+     * @brief Get the object subsystem object
+     * 
+     * @return object_system* 
+     */
     object_system* get_object_subsystem();
 
+    /**
+     * @brief Saves system data to disk
+     * 
+     */
     void save();
+    /**
+     * @brief Loads system data from disk
+     * 
+     */
     void load();
 
+    /**
+     * @brief Checks if it is first run
+     * 
+     * @return true 
+     * @return false 
+     */
     static bool is_first_run();
+    /**
+     * @brief Generates lock file after initialization
+     * 
+     */
     static void generate_lock_file();
+    /**
+     * @brief Get ther main system object
+     * 
+     * @return apparatus* 
+     */
     static apparatus* instance();
+    /**
+     * @brief Initializes system on start
+     * 
+     */
     static void init();
+    /**
+     * @brief Shuts system down in the end
+     * 
+     */
     static void shutdown();
 };
 
diff --git a/sea_transport/system/auth_system.h b/sea_transport/system/auth_system.h
index 8d0d3bf..adabce6 100644
--- a/sea_transport/system/auth_system.h
+++ b/sea_transport/system/auth_system.h
@@ -6,19 +6,66 @@
 #include "../entities/user_entity.h"
 
 
+/**
+ * @brief User's manipulation subsystem
+ * 
+ */
 class auth_system {
 private:
+    //! Subsystem's users collection
     QVector<user_entity> _users;
 public:
+    /**
+     * @brief Construct a new auth system object
+     * 
+     */
     auth_system() = default;
 
+    /**
+     * @brief Get user
+     * 
+     * @param login user's login
+     * @param success operation success reference
+     * @return user_entity* 
+     */
     user_entity* get_user(const QString &login, bool &success);
+    /**
+     * @brief Remove user from subsystem
+     * 
+     * @param login user's login
+     * @return true 
+     * @return false 
+     */
     bool remove_user(const QString &login);
+    /**
+     * @brief Registeer new user in system
+     * 
+     * @param login new user's login
+     * @param password new usere's password
+     * @param role new user's role
+     * @return true 
+     * @return false 
+     */
     bool register_user(const QString &login, const QString &password, UserRole role);
 
+    /**
+     * @brief Get subsystem immutable users collection
+     * 
+     * @return const QVector<user_entity>& 
+     */
     const QVector<user_entity>& users() const;
 
+    /**
+     * @brief Reads subsytem's data from disk
+     * 
+     * @param stream read stream
+     */
     void deserialize_data(QDataStream *stream);
+    /**
+     * @brief Writes subsytem's data to disk
+     * 
+     * @param stream write stream
+     */
     void serialize_data(QDataStream *stream);
 };
 
diff --git a/sea_transport/system/object_system.h b/sea_transport/system/object_system.h
index 40d09f1..f7a973f 100644
--- a/sea_transport/system/object_system.h
+++ b/sea_transport/system/object_system.h
@@ -7,27 +7,99 @@
 #include "../entities/vessel_entity.h"
 
 
+/**
+ * @brief Object's manipulation subsystem
+ * 
+ */
 class object_system {
 private:
+    //! Subsystem's DP collection
     QVector<dpoint_entity> _dpoints;
+    //! Subsystem's vessels collection
     QVector<vessel_entity> _vessels;
 
 public:
+    /**
+     * @brief Construct a new object system object
+     * 
+     */
     object_system() = default;
 
+    /**
+     * @brief Get DP object
+     * 
+     * @param oid DP's ID
+     * @param success operation success reference
+     * @return dpoint_entity* 
+     */
     dpoint_entity* get_dpoint(entity_id oid, bool &success);
+    /**
+     * @brief Remove DP from subsystem
+     * 
+     * @param oid DP's ID
+     * @return true 
+     * @return false 
+     */
     bool remove_dpoint(entity_id oid);
+    /**
+     * @brief Add DP to subsystem
+     * 
+     * @param dpoint new DP object
+     * @return true 
+     * @return false 
+     */
     bool add_dpoint(dpoint_entity dpoint);
 
+    /**
+     * @brief Get vessel object
+     * 
+     * @param oid vessel ID
+     * @param success operation success reference
+     * @return vessel_entity* 
+     */
     vessel_entity* get_vessel(entity_id oid, bool &success);
+    /**
+     * @brief Remove vessel from subsystem
+     * 
+     * @param oid vessel's ID
+     * @return true 
+     * @return false 
+     */
     bool remove_vessel(entity_id oid);
+    /**
+     * @brief Add vessel to subsystem
+     * 
+     * @param dpoint 
+     * @return true 
+     * @return false 
+     */
     bool add_vessel(vessel_entity dpoint);
 
 
+    /**
+     * @brief Get subsystem immutable DP collection
+     * 
+     * @return const QVector<dpoint_entity> 
+     */
     const QVector<dpoint_entity> dpoints() const;
+    /**
+     * @brief Get subsystem immutable vessel collection
+     * 
+     * @return const QVector<vessel_entity> 
+     */
     const QVector<vessel_entity> vessels() const;
 
+    /**
+     * @brief Reads subsytem's data from disk
+     * 
+     * @param stream read stream
+     */
     void deserialize_data(QDataStream *stream);
+    /**
+     * @brief Writes subsytem's data to disk
+     * 
+     * @param stream write stream
+     */
     void serialize_data(QDataStream *stream);
 };