Use UML to create Class, Sequence, Use Case, Activity, or State diagrams
Unified Modeling Language (UML) is a standard way to draw software models. Use the UML templates in Visio for sketching out designs, or for documenting existing designs.
Visio has templates for UML 2.0 versions of several diagram types:
Use Case diagram
To find the right template to start from, go to File > New and, in the search box, type the name of the diagram you want (or type UML to find all the templates).
Using the UML shapes
To make prototyping easy and quick, UML shapes are simple and freeform. Add information like attributes, operations, and so on, by clicking the individual text box you want to edit inside the UML shape. When just that text box is selected inside the shape, type your text. If you’ve added text and you want to change it later, double-click the text box to open it for editing (if you just select the box and start typing without double-clicking, the original text will be deleted).
Connect shapes by using AutoConnect or the specialized connectors you’ll find in the stencils. To use a specialized connector, drop it on the drawing page and then drag the ends and drop them on the middle of the shapes you want to connect, or onto specific connection points along the sides of the shapes.
Show or hide optional elements
Some shapes have optional elements that you can show to include more information, or hide to simplify the diagram.
Select the entire shape. The selection outline with the control handles should be along the outside of the entire shape, showing that no individual shapes inside the group are selected. You might have to click on an empty part of the page to clear the selection, and then click on a non-text part of the shape, or else click a selected sub-shape more than once until the selection moves to the entire shape.
Right-click the selected shape. The optional elements are listed in the right-click menu, for example Show Parameter and Show Stereotype.