diff --git a/application/Espo/Tools/Import/Import.php b/application/Espo/Tools/Import/Import.php
index 23dae063b5..4a2cd55a2c 100644
--- a/application/Espo/Tools/Import/Import.php
+++ b/application/Espo/Tools/Import/Import.php
@@ -71,15 +71,18 @@ class Import
 
     private const DEFAULT_TIME_FORMAT = 'HH:mm';
 
+    /**
+     * @var string[]
+     */
     private $attributeList = [];
 
-    private $params;
+    private Params $params;
 
-    private $id = null;
+    private ?string $id = null;
 
-    private $attachmentId = null;
+    private ?string $attachmentId = null;
 
-    private $entityType = null;
+    private ?string $entityType = null;
 
     private $aclManager;
 
@@ -165,6 +168,8 @@ class Import
 
     /**
      * Set an attribute list to parse from CSV rows.
+     *
+     * @param string[] $attributeList
      */
     public function setAttributeList(array $attributeList): self
     {
@@ -386,6 +391,11 @@ class Import
             ->withCountUpdated(count($result->updatedIds));
     }
 
+    /**
+     * @param string[] $attributeList
+     * @param mixed[] $row
+     * @throws Error
+     */
     private function importRow(array $attributeList, array $row): ?stdClass
     {
         $params = $this->params;
@@ -627,6 +637,9 @@ class Import
         }
     }
 
+    /**
+     * @param mixed $value
+     */
     private function processRowItem(Entity $entity, string $attribute, $value, stdClass $valueMap): void
     {
         $params = $this->params;
@@ -801,6 +814,7 @@ class Import
     }
 
     /**
+     * @param mixed $value
      * @return mixed
      */
     private function parseValue(Entity $entity, string $attribute, $value)
@@ -894,6 +908,7 @@ class Import
     }
 
     /**
+     * @param mixed $value
      * @return mixed
      */
     private function prepareAttributeValue(Entity $entity, string $attribute, $value)
@@ -909,7 +924,14 @@ class Import
         return $value;
     }
 
-    private function parsePersonName($value, string $format): array
+    /**
+     * @return array{
+     *   firstName: ?string,
+     *   lastName: ?string,
+     *   middleName?: ?string,
+     * }
+     */
+    private function parsePersonName(string $value, string $format): array
     {
         $firstName = null;
         $lastName = $value;
@@ -929,6 +951,7 @@ class Import
 
             case 'l f':
                 $pos = strpos($value, ' ');
+
                 if ($pos) {
                     $lastName = trim(substr($value, 0, $pos));
                     $firstName = trim(substr($value, $pos + 1));
@@ -1002,6 +1025,9 @@ class Import
         ];
     }
 
+    /**
+     * @return string[]
+     */
     private function readCsvString(
         string &$string,
         string $separator = ';',
diff --git a/application/Espo/Tools/Import/Params.php b/application/Espo/Tools/Import/Params.php
index c092b8b087..4cc9dc734f 100644
--- a/application/Espo/Tools/Import/Params.php
+++ b/application/Espo/Tools/Import/Params.php
@@ -40,39 +40,42 @@ class Params
 
     public const ACTION_UPDATE = 'update';
 
-    private $action = null;
+    private ?string $action = null;
 
-    private $delimiter = null;
+    private ?string $delimiter = null;
 
-    private $textQualifier = null;
+    private ?string $textQualifier = null;
 
-    private $personNameFormat = null;
+    private ?string $personNameFormat = null;
 
-    private $idleMode = false;
+    private bool $idleMode = false;
 
-    private $manualMode = false;
+    private bool $manualMode = false;
 
-    private $silentMode = false;
+    private bool $silentMode = false;
 
-    private $headerRow = false;
+    private bool $headerRow = false;
 
-    private $skipDuplicateChecking = false;
+    private bool $skipDuplicateChecking = false;
 
-    private $startFromLastIndex = false;
+    private bool $startFromLastIndex = false;
 
+    /**
+     * @var int[]
+     */
     private $updateBy = [];
 
-    private $defaultValues;
+    private stdClass $defaultValues;
 
-    private $dateFormat = null;
+    private ?string $dateFormat = null;
 
-    private $timeFormat = null;
+    private ?string $timeFormat = null;
 
-    private $currency = null;
+    private ?string $currency = null;
 
-    private $timezone = null;
+    private ?string $timezone = null;
 
-    private $decimalMark = null;
+    private ?string $decimalMark = null;
 
     private function __construct()
     {
@@ -129,6 +132,9 @@ class Params
         return $this->startFromLastIndex;
     }
 
+    /**
+     * @return int[]
+     */
     public function getUpdateBy(): array
     {
         return $this->updateBy;
@@ -249,6 +255,9 @@ class Params
         return $obj;
     }
 
+    /**
+     * @param int[] $updateBy
+     */
     public function withUpdateBy(array $updateBy): self
     {
         $obj = clone $this;
@@ -258,7 +267,7 @@ class Params
     }
 
     /**
-     * @param stdClass|array|null $defaultValues
+     * @param stdClass|array<string,mixed>|null $defaultValues
      */
     public function withDefaultValues($defaultValues): self
     {
@@ -323,7 +332,7 @@ class Params
     }
 
     /**
-     * @param stdClass|array|null $params
+     * @param stdClass|array<string,mixed>|null $params
      */
     public static function fromRaw($params): self
     {
@@ -355,6 +364,9 @@ class Params
         return $obj;
     }
 
+    /**
+     * @return array<string,mixed>
+     */
     public function getRaw(): array
     {
         return [
diff --git a/application/Espo/Tools/Import/Result.php b/application/Espo/Tools/Import/Result.php
index 438811da11..872df3980c 100644
--- a/application/Espo/Tools/Import/Result.php
+++ b/application/Espo/Tools/Import/Result.php
@@ -33,13 +33,13 @@ use stdClass;
 
 class Result
 {
-    private $id = null;
+    private ?string $id = null;
 
-    private $countCreated = 0;
+    private int $countCreated = 0;
 
-    private $countUpdated = 0;
+    private int $countUpdated = 0;
 
-    private $manualMode = false;
+    private bool $manualMode = false;
 
     public function getId(): ?string
     {
diff --git a/application/Espo/Tools/Import/Service.php b/application/Espo/Tools/Import/Service.php
index c9ecd528d1..4def79a605 100644
--- a/application/Espo/Tools/Import/Service.php
+++ b/application/Espo/Tools/Import/Service.php
@@ -68,6 +68,11 @@ class Service
         $this->acl = $acl;
     }
 
+    /**
+     * @param string[] $attributeList
+     * @param string $attachmentId
+     * @throws Forbidden
+     */
     public function import(
         string $entityType,
         array $attributeList,