What is the use case for automatically creating a work object on login? Once you are logged in, you can use the Create menu to create a work object or create your own buttons or links as desired.

If you are looking for a link outside the system that you can click, one of these options may be helpful.

https://pdn.pega.com/sites/pdn.pega.com/files/help_v731/procomhelpmain.htm#mobile/concepts/mob-use-snapstart-module-outside-sdk-con.htm

https://pdn.pega.com/products/pega-web-mashup