Global variables are the variables used to reference the general information about the current user or your organization on a page.

Example:

Global variables must be referenced using VISUALFORCE expression syntax to be EVALUATED, for example, {!$User.Name}.

List of available global variables are as below:

1. $Action
2. $Api
3. $Component
4. $ComponentLabel
5. $CurrentPage
6. $Label
7. $Label.Site
8. $ObjectType
9. $Organization
10. $Page
11. $Profile
12. $Resource
13. $SControl
14. $Setup
15. $Site
16. $User
17. $UserRole
18. $System.OriginDateTime 
19. $ User.UITheme and $User.UIThemeDisplayed

Global variables are the variables used to reference the general information about the current user or your organization on a page.

Example:

Global variables must be referenced using Visualforce expression syntax to be evaluated, for example, {!$User.Name}.

List of available global variables are as below:

1. $Action
2. $Api
3. $Component
4. $ComponentLabel
5. $CurrentPage
6. $Label
7. $Label.Site
8. $ObjectType
9. $Organization
10. $Page
11. $Profile
12. $Resource
13. $SControl
14. $Setup
15. $Site
16. $User
17. $UserRole
18. $System.OriginDateTime 
19. $ User.UITheme and $User.UIThemeDisplayed