diff --git a/docs/en/Tutorials/Part-1.md b/docs/en/Tutorials/Part-1.md
index 6795204936..e5a8750f39 100644
--- a/docs/en/Tutorials/Part-1.md
+++ b/docs/en/Tutorials/Part-1.md
@@ -368,7 +368,7 @@ public class CreateUpdateBookDto
 {
     [Required]
     [StringLength(128)]
-    public string Name { get; set; }
+    public string Name { get; set; } = string.Empty;
 
     [Required]
     public BookType Type { get; set; } = BookType.Undefined;
diff --git a/docs/en/Tutorials/Part-10.md b/docs/en/Tutorials/Part-10.md
index d06cea6b6e..601905f522 100644
--- a/docs/en/Tutorials/Part-10.md
+++ b/docs/en/Tutorials/Part-10.md
@@ -788,7 +788,7 @@ public class CreateModalModel : BookStorePageModel
 
         [Required]
         [StringLength(128)]
-        public string Name { get; set; }
+        public string Name { get; set; } = string.Empty;
 
         [Required]
         public BookType Type { get; set; } = BookType.Undefined;
@@ -871,7 +871,7 @@ public class EditModalModel : BookStorePageModel
 
         [Required]
         [StringLength(128)]
-        public string Name { get; set; }
+        public string Name { get; set; } = string.Empty;
 
         [Required]
         public BookType Type { get; set; } = BookType.Undefined;
diff --git a/docs/en/Tutorials/Part-6.md b/docs/en/Tutorials/Part-6.md
index 40b334808c..2cb525b4a4 100644
--- a/docs/en/Tutorials/Part-6.md
+++ b/docs/en/Tutorials/Part-6.md
@@ -75,9 +75,9 @@ public class Author : FullAuditedAggregateRoot<Guid>
 
     internal Author(
         Guid id,
-        [NotNull] string name,
+        string name,
         DateTime birthDate,
-        [CanBeNull] string shortBio = null)
+        string? shortBio = null)
         : base(id)
     {
         SetName(name);
@@ -85,13 +85,13 @@ public class Author : FullAuditedAggregateRoot<Guid>
         ShortBio = shortBio;
     }
 
-    internal Author ChangeName([NotNull] string name)
+    internal Author ChangeName(string name)
     {
         SetName(name);
         return this;
     }
 
-    private void SetName([NotNull] string name)
+    private void SetName(string name)
     {
         Name = Check.NotNullOrWhiteSpace(
             name, 
@@ -146,9 +146,9 @@ public class AuthorManager : DomainService
     }
 
     public async Task<Author> CreateAsync(
-        [NotNull] string name,
+        string name,
         DateTime birthDate,
-        [CanBeNull] string shortBio = null)
+        string? shortBio = null)
     {
         Check.NotNullOrWhiteSpace(name, nameof(name));
 
@@ -167,8 +167,8 @@ public class AuthorManager : DomainService
     }
 
     public async Task ChangeNameAsync(
-        [NotNull] Author author,
-        [NotNull] string newName)
+        Author author,
+        string newName)
     {
         Check.NotNull(author, nameof(author));
         Check.NotNullOrWhiteSpace(newName, nameof(newName));
diff --git a/docs/en/Tutorials/Part-8.md b/docs/en/Tutorials/Part-8.md
index 7ea3c6cbae..a1563f6b2c 100644
--- a/docs/en/Tutorials/Part-8.md
+++ b/docs/en/Tutorials/Part-8.md
@@ -123,12 +123,12 @@ public class CreateAuthorDto
 {
     [Required]
     [StringLength(AuthorConsts.MaxNameLength)]
-    public string Name { get; set; }
+    public string Name { get; set; }  = string.Empty;
 
     [Required]
     public DateTime BirthDate { get; set; }
     
-    public string ShortBio { get; set; }
+    public string? ShortBio { get; set; }
 }
 ````
 
@@ -146,12 +146,12 @@ public class UpdateAuthorDto
 {
     [Required]
     [StringLength(AuthorConsts.MaxNameLength)]
-    public string Name { get; set; }
+    public string Name { get; set; } = string.Empty;
 
     [Required]
     public DateTime BirthDate { get; set; }
     
-    public string ShortBio { get; set; }
+    public string? ShortBio { get; set; }
 }
 ````
 
diff --git a/docs/en/Tutorials/Part-9.md b/docs/en/Tutorials/Part-9.md
index 704d5f016b..358448c4d2 100644
--- a/docs/en/Tutorials/Part-9.md
+++ b/docs/en/Tutorials/Part-9.md
@@ -331,14 +331,14 @@ public class CreateModalModel : BookStorePageModel
     {
         [Required]
         [StringLength(AuthorConsts.MaxNameLength)]
-        public string Name { get; set; }
+        public string Name { get; set; } = string.Empty;
 
         [Required]
         [DataType(DataType.Date)]
         public DateTime BirthDate { get; set; }
 
         [TextArea]
-        public string ShortBio { get; set; }
+        public string? ShortBio { get; set; }
     }
 }
 ```
@@ -454,14 +454,14 @@ public class EditModalModel : BookStorePageModel
 
         [Required]
         [StringLength(AuthorConsts.MaxNameLength)]
-        public string Name { get; set; }
+        public string Name { get; set; } = string.Empty;
 
         [Required]
         [DataType(DataType.Date)]
         public DateTime BirthDate { get; set; }
 
         [TextArea]
-        public string ShortBio { get; set; }
+        public string? ShortBio { get; set; }
     }
 }
 ```