diff --git a/kotpass/src/main/kotlin/app/keemobile/kotpass/constants/BasicField.kt b/kotpass/src/main/kotlin/app/keemobile/kotpass/constants/BasicField.kt
index 8f9552e..a51e0d4 100644
--- a/kotpass/src/main/kotlin/app/keemobile/kotpass/constants/BasicField.kt
+++ b/kotpass/src/main/kotlin/app/keemobile/kotpass/constants/BasicField.kt
@@ -1,5 +1,8 @@
 package app.keemobile.kotpass.constants
 
+/**
+ * Basic fields which should be added to every entry.
+ */
 enum class BasicField(val key: String) {
     Title("Title"),
     UserName("UserName"),
diff --git a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomDataValue.kt b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomDataValue.kt
index a559665..d39b7a1 100644
--- a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomDataValue.kt
+++ b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomDataValue.kt
@@ -2,6 +2,9 @@ package app.keemobile.kotpass.models
 
 import java.time.Instant
 
+/**
+ * Arbitrary string data holder for database/group/entry metadata.
+ */
 data class CustomDataValue(
     val value: String,
     val lastModified: Instant? = null
diff --git a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomIcon.kt b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomIcon.kt
index 41acc24..8f2d320 100644
--- a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomIcon.kt
+++ b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/CustomIcon.kt
@@ -2,6 +2,14 @@ package app.keemobile.kotpass.models
 
 import java.time.Instant
 
+/**
+ * Extra icon added by user to the database. Can be used
+ * for customizing groups and entries.
+ *
+ * @property data contains the icon image data as binary blob.
+ * @property name optionally given to icon.
+ * @property lastModified timestamp.
+ */
 data class CustomIcon(
     val data: ByteArray,
     val name: String?,
diff --git a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/EntryFields.kt b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/EntryFields.kt
index a2f58eb..9905e53 100644
--- a/kotpass/src/main/kotlin/app/keemobile/kotpass/models/EntryFields.kt
+++ b/kotpass/src/main/kotlin/app/keemobile/kotpass/models/EntryFields.kt
@@ -3,6 +3,10 @@ package app.keemobile.kotpass.models
 import app.keemobile.kotpass.constants.BasicField
 import app.keemobile.kotpass.cryptography.EncryptedValue
 
+/**
+ * Wraps [Map] to override [equals] and take into
+ * account order of items in equality checks.
+ */
 class EntryFields(
     private val fields: Map<String, EntryValue>
 ) : Map<String, EntryValue> by fields {
@@ -46,6 +50,10 @@ class EntryFields(
     companion object {
         fun of(vararg pairs: Pair<String, EntryValue>) = EntryFields(mapOf(*pairs))
 
+        /**
+         * Creates [EntryFields] which is populated with empty [BasicField]
+         * values as required by KeePass contract.
+         */
         fun createDefault() = EntryFields(
             buildMap {
                 BasicField