Document behavior of generating destination path when copying

README.md

@@ -77,21 +77,23 @@ To generate a project from the template:
 
 -   Or in Python code, programmatically:
 
-    ```python
-    from copier import run_copy
+        ```python
+        from copier import run_copy
 
-    # Create a project from a local path
-    run_copy("path/to/project/template", "path/to/destination")
+        # Create a project from a local path
+        run_copy("path/to/project/template", "path/to/destination")
 
-    # Or from a Git URL.
-    run_copy("https://github.com/copier-org/copier.git", "path/to/destination")
+        # Or from a Git URL.
+        run_copy("https://github.com/copier-org/copier.git", "path/to/destination")
 
-    # You can also use "gh:" as a shortcut of "https://github.com/"
-    run_copy("gh:copier-org/copier.git", "path/to/destination")
+        # You can also use "gh:" as a shortcut of "https://github.com/"
+        run_copy("gh:copier-org/copier.git", "path/to/destination")
 
-    # Or "gl:" as a shortcut of "https://gitlab.com/"
-    run_copy("gl:copier-org/copier.git", "path/to/destination")
-    ```
+        # Or "gl:" as a shortcut of "https://gitlab.com/"
+        run_copy("gl:copier-org/copier.git", "path/to/destination")
+        ```
+
+    If `path/to/destination` doesn't exist, Copier will create the directory.
 
 ## Basic concepts
 

docs/generating.md

@@ -18,6 +18,10 @@ Or within Python code:
 copier.run_copy("path/to/project/template", "path/to/destination")
 ```
 
+If `path/to/destination` doesn't exist, Copier will create the directory and populate it
+with the generated files. If `path/to/destination` exists, it must be writable (not
+read-only).
+
 The "template" parameter can be a local path, an URL, or a shortcut URL:
 
 -   GitHub: `gh:namespace/project`