You can add, edit, show, and delete dimensions; you can also specify how dimensions appear.
What's New: 2019
If you are new to Inventor we recommend looking over the Getting Started and Guided Tutorials that pertain to sketches.
Brief video of creating sketch dimensions
 Constrain panel
 
		Constrain panel 
		  Dimension
 
		Dimension 
		 (2D sketch) or 
		3D Sketch tab
 (2D sketch) or 
		3D Sketch tab  Constrain panel
 
		Constrain panel 
		  Dimension
 
		Dimension 
		 (3D sketch).
 (3D sketch). 
	 In a 3D sketch, the dimension text is parallel to a plane created by the two selections.
In a 3D sketch, you can enable or disable adding dimensions to geometry as you sketch. Click Dynamic Dimension in the status bar to enable or disable the ability to add dimensions in the value box as you sketch. You can also press Ctrl + D to toggle Dynamic Dimension on or off.
 , click-drag the dimension to a new position.
, click-drag the dimension to a new position. 
	 Make dimensions visible so you can edit them.
 
 
  
Only normal dimensions can be manually edited. Convert driven dimensions to normal dimensions so you can edit them.
In an over-constrained sketch, you may have to first convert other dimensions to driven (reference) parameters, or remove some dimensions or constraints, before you can convert driven dimensions to normal dimensions.
 Format panel > Driven Dimension
 Format panel > Driven Dimension 
		 (2D sketches) or 3D Sketch tab
 (2D sketches) or 3D Sketch tab  Format panel
 Format panel  Driven Dimension
 Driven Dimension 
		 (3D sketches) to deselect it and make the dimension or dimensions normal.
 (3D sketches) to deselect it and make the dimension or dimensions normal.