Hi Chandra,
You can create workflow for any table. Just create a new workflow and In workflow properties, give table name as Incident and provide the necessary conditions in the field 'If condition matches' .If the field is not present in the form then you have to add it to the form by right click -configure -form layout- then add the field.
Now the workflow will be automatically attached when the condition satisfies.
Creating a Workflow - ServiceNow Wiki
https://developer.servicenow.com/app.do#!/training/article/app_store_learn_path_build_app_fuji_c_Wor...
If you want to refer a standard incident workflow then refer the link below:
Best Practice - Incident Resolution Workflow - ServiceNow Wiki
