A transform is an adjustment of an object’s position, orientation, or scale, relative to the 3D world (or world space) in which you’re working.

Changing a model by changing its position, rotation, or scale
You can apply three basic types of transform to an object:
And a fourth transform command lets you position an object automatically on an underlying surface:
This section presents brief topics to help you quickly start learning how to transform objects and how to animate your transforms.
In some cases, an object might fail to move or rotate, even when the proper command is active and the object is selected. This could be due to one of the following reasons:
To transform an object using the main toolbar:
On the main toolbar, click one of the three transform buttons: (Select And Move), (Select And Rotate), or (Select And Uniform Scale). These buttons are usually referred to as Move, Rotate, and Scale.
Alternatively, to position an object on another object's surface, click (Select And Place).
Position the mouse over the object you want to transform.
Drag the mouse to apply the transform.
If you start the drag over an unselected object, it becomes selected and is also transformed.
You can restrict transforms to one or two axes easily with the Using Transform Gizmos.
To cancel a transform:
To transform an object from the quad menu:
To use the Transform Type-In dialog:
Choose Edit menu > Transform Type-In to display the dialog.
Apply a transform to a selected object.
You can do any of the following, switching from one to the other as required.
Enter to apply the transform change to the selection.For example, if Move is active, the dialog fields read out both the absolute and offset positions of the selected object in world space. If no object is selected, the fields turn gray.
To use transform type-in on the status bar:
Select an object or a group of objects.
On the main toolbar, choose a transform (Move, Rotate, or Scale) to perform on the objects.
On the status bar, you can do any of the following, switching from one to another as required:
Type a value in an axis field and press Enter to apply the transform change to the selection. The Absolute/Offset toggle, to the right of the X, Y, and Z fields, lets you switch between entering values that are absolute (in world space) or offset (relative to the selection's present position, orientation, and dimensions).
Drag a spinner in an axis field to update the selection.
Drag the object to apply the transform and read the resulting change in the X, Y, and Z fields.