diff --git a/Documentation/ProjectFile/prj/process_variables/i_process_variables.md b/Documentation/ProjectFile/prj/process_variables/i_process_variables.md
index 576add64edccf5d980a0ff86143dc43a7109a788..5d091f0a6e6bffa78b1df6b54fb48b00267aa9c3 100644
--- a/Documentation/ProjectFile/prj/process_variables/i_process_variables.md
+++ b/Documentation/ProjectFile/prj/process_variables/i_process_variables.md
@@ -1 +1 @@
-\ogs_missing_documentation
+Contains definitions of process variables.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/i_boundary_conditions.md b/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/i_boundary_conditions.md
index 576add64edccf5d980a0ff86143dc43a7109a788..390cd469ebe1623cabd0e1f5249b22e33c127a99 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/i_boundary_conditions.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/i_boundary_conditions.md
@@ -1 +1 @@
-\ogs_missing_documentation
+Contains boundary conditions for the process variable.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/t_boundary_condition.md b/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/t_boundary_condition.md
index 576add64edccf5d980a0ff86143dc43a7109a788..fcf9ace11720b05f89de0d1cceadf9ef42b71d63 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/t_boundary_condition.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/boundary_conditions/t_boundary_condition.md
@@ -1 +1,3 @@
-\ogs_missing_documentation
+Specifies a single boundary condition.
+
+See \ref ogs_file_param__boundary_condition.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/i_process_variable.md b/Documentation/ProjectFile/prj/process_variables/process_variable/i_process_variable.md
index 576add64edccf5d980a0ff86143dc43a7109a788..c13a3da077220f22bb4b1a88a1c31a901f9fb51a 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/i_process_variable.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/i_process_variable.md
@@ -1 +1,4 @@
-\ogs_missing_documentation
+Defines a single process variable.
+
+A process variable is a primary variable for which some process is solved. For a
+process variable initial and boundary conditions can be specified.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/t_components.md b/Documentation/ProjectFile/prj/process_variables/process_variable/t_components.md
index 576add64edccf5d980a0ff86143dc43a7109a788..f00a279ebf5056d69cb8663303920c1a1c9e3e75 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/t_components.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/t_components.md
@@ -1 +1,4 @@
-\ogs_missing_documentation
+Sets the number of components of the process variable.
+
+It is one for scalar variables and greater than one for vectorial (or
+theoretically even tensorial) process variables.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/t_initial_condition.md b/Documentation/ProjectFile/prj/process_variables/process_variable/t_initial_condition.md
index 576add64edccf5d980a0ff86143dc43a7109a788..faa2bccc16d3cb544dbe73ac5ab89e2c7c935abc 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/t_initial_condition.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/t_initial_condition.md
@@ -1 +1,3 @@
-\ogs_missing_documentation
+Initial condition for the process variable.
+
+This setting references a \ref ogs_file_param__parameter "parameter" by name.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/t_name.md b/Documentation/ProjectFile/prj/process_variables/process_variable/t_name.md
index 576add64edccf5d980a0ff86143dc43a7109a788..4e07f42e4a5b791a85f2b4f0c0e14f12e16f2ba3 100644
--- a/Documentation/ProjectFile/prj/process_variables/process_variable/t_name.md
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/t_name.md
@@ -1 +1 @@
-\ogs_missing_documentation
+Name under which the process variable can be referenced.