Merge pull request #594 from opengisch:m-kuhn-patch-1

Improve variable documentation

Author: beanzmo

documentation/how-to/variables.en.md

@@ -5,37 +5,41 @@ tx_slug: documentation_how-to_variables
 
 # Variables
 
-QField allows user to add and edit expression variables.
+QField allows users to add and edit expression variables.
 These can be used for a wide range of applications, including data-defined symbology, setting default field values, controlling print layout and application behavior, and much more.
-See [the relevant QGIS documentation](https://docs.qgis.org/3.40/en/docs/user_manual/introduction/general_tools.html#storing-values-in-variables) for more information.
+See [the relevant QGIS documentation](https://docs.qgis.org/latest/en/docs/user_manual/introduction/general_tools.html#storing-values-in-variables) for more information.
 
-QField supports two main types of variables:
+QField supports two main types of custom variables:
 
 - **Project Variables:** Project-bound variables defined within the project file.
-- **Global Variables:** Application-wide global variables with a set of read-only variables matching those found in QGIS.
+- **Global Variables:** Application-wide global variables with a set of read-only variables.
+
+
 
 ## Project Variables
 
-Project variables are defined and managed directly within your QGIS project.
+Project variables are defined and managed directly within the QGIS project on your desktop.
 They allow you to add custom variables that are only relevant in the context of a specific project.
 QField users can edit those variables, with modified values remembered across sessions.
 
 ## Global Variables
 
-New global variables can be added or modified once and will be injected into all projects opened in QField across sessions.
-Global variables can be used to add a unique identifier across a fleet of QField devices for example, or determine the language for a given QField user.
-Since they are not bound to specific projects and are defined locally, they make for a great way to customize experience for multiple users sharing the same projects.
+QField comes pre-configured with some read-only global variables which are visible in *Settings > Variables*.
+New variables can be added or modified and will be available in QField across sessions.
+
+!!! Information
+    The read-only variables differ from device to device. These reflect the global variables from the specific QGIS version that was being used to develop the installed version of QField.
 
 ## Variable Management in QField
 
 Variables are managed directly on your device and are accessible in all available QField projects.
-When you access the variables list in QField ( Settings > Variables ), you will find a consolidated and organized view of all available variables.
+When you access the variables list in QField ( *Settings > Variables* ), you will find a consolidated and organized view of all available variables.
 
 ### Variable configuration
 
 :material-tablet: Fieldwork
 
-To configure a device-specific variable, follow these steps:
+To configure a application-specific variable, follow these steps:
 
 1. Open **Settings** in QField.
 2. Navigate to the **Variables** tab.
@@ -44,7 +48,19 @@ Here you will see a list of all variables currently applicable to your project.
 To add a new variable:
 
 1. Click on *Add a new variable* at the bottom of the variable list.
-2. Enter the name and value for your new variable.
+2. Enter the name and value for your new variable and save.
+
+### Useful Examples
+
+Common variables to use are:
+
+- **@cloud_username** to incorporate the details of the individual users in a project.
+
+**Note**: If you are not using QFieldCloud you can add a unique identifier instead.
+
+- **@qgis_locale** to use the currently set language of QGIS/QField.
+
+Since the application-wide variables are not bound to specific projects and are defined locally, they are a great way to optimize the fieldwork experience for multiple users sharing the same projects.
 
 !![Configuration of editable variables in addition to the
 pre-defined system variables.](../assets/images/configure_global_variables.png, 400px)