Hello,
Although many of us are aware of creating a t-code for Web Dynpro application to launch it in internet explorer, thought to create a small document for quick reference for those who need help.
Go to transaction code se93 and provide t-code name you want to create and press on Create button.

Provide Transaction text and choose Transaction with parameters (parameter transaction) radio button

Under Default values for section give Transaction = WDYID and select Skip initial screen radio button.

In Default values table control give the below
| Name of screen field | Value |
|---|---|
STARTMODE | BROWSER |
| APPLICATION | Give Application Name |

On execution of t-code application is launched in web browser. If we want to launch it in sap pass GUI as value for STARTMODE.
Hope this helps.