Answer:
You can use the Maxlenght property to specify the maximum amount of characters that can be typed in a textbox.
Explanation:
TextBox.Maxlenght property gets or sets the maximum number of characters that you can manually entered in a textbox. Normally, the default value is 0, which means the input in the textbox will have no limit.
Example:
myPersonalTextBox.MaxLength = 150;
Through the MaxLength property, the textbox in the example myPersonalTextBox, was set to a maximum of 150 characters that a user could manually input.