Simple Types Fields
The Simple types fields represent an individual value. An individual value may have multiple properties, such as the attributes in an Image field or the images, links in a Rich Text field. These fields are directly output or displayed on the web pages.
Checkbox
This field is used as a Boolean in Sitecore. It displays as a toggle button in Sitecore. If the user has checked the checkbox then Sitecore stores the value 1. If the user does not check the checkbox then Sitecore stores a blank value. If the checked box is checked then it is used as True else it is used as False. We use Sitecore.Data.Fields.CheckboxField.Checked to check whether the check box is checked or not.
Date
This field is used for storing Date. It allows users to select a date manually or you can select the date from the calendar widget. The format of date is mm/dd/yyyy. If you enter the date in format mm-dd-yyyy then it will automatically convert it into mm/dd/yyyy.
Datetime
This field is used for Date and Time. It provides the user with a widget that allows the user to select or enter a date and time manually. Date field does not provide the option to select the time while Datetime does. Sitecore stores the entered content as a text (string) which is of the format yyyyMMddTHHmmss. It uses the ISO format. If the user does not enter a time then Sitecore stores the value as 000000. The value stored represents the local time for the Web server. You can click on the Now button to set the date and time according to the system.
Image
The Image field allows the users to select an image from the media library and allows them to specify image properties like alternate text, Width, Height, etc. Users can click browse to open the Media Library for selecting the desired file. The Source property of an Image field controls the selected item in the Media Browser.
Integer
The Integer field type is used to store a single line of text having validation for integer values. If you try to enter anything except integer then it will give an error and not let you save the text.
Number
The Number field type is used for storing a single line of text having validation for number values. The difference between Integer and Number Field is that Integer will not allow decimal values while Number will allow decimal as well.
Multi-Line Text
We use the Multi-line field type for simple text values spanning multiple lines. This field has no validation and there is no Rich Text support for fields of this type.
Password
Password field type stores a single line of text with a mask for password values. The characters are masked so that others cannot read them.
Single-Line Text
As the name suggests Single-Line text. This field type stores a single line of text.
Rich Text
The Rich Text field is a type of field that stores the data as HTML text. It displays the contents as a browser would display the source HTML. The Design button will display the content without HTML while the HTML button will display the content in HTML form with all necessary tags.
File
The File field type allows the user to select an item from the media library. You can click Open file to open the Media Browser and select the desired file from the media library. You can search the file using the Search option or you can select the file from the content tree using the Browse option. You can even upload the file. After selecting the file you can download the file or you can view the file.
References
The simple field types - https://doc.sitecore.com/xp/en/developers/90/sitecore-experience-manager/the-simple-field-types.html
Field types in Sitecore - https://learnsitecore.jprajapati.in/2017/03/29/field-types-in-sitecore/