In a task after filling the form i will submit the task. How can I know how much

If it's activity chained with another task then you can look at the Process Details - Process Nodes. Just make sure to keep in mind that the duration for the task itself includes the whole amount of time since its creation until the submission so you better measure the time of the nodes between activity chained tasks.

Thanks for reply.If we add all times of nodes involved in process it would be fine to estimate?

Just if you're measuring the time it'll take for a user to move from one task to the next one assuming they're activity chained. The measurement should include only the nodes in between these two tasks.

Its single task It's not connected to other task.Just wanted to know how much time its taking after submit because thinking to add more validations to that page.

Then the time it takes to submit is not relevant, once the user clicks "Submit" it's all back-end and I don't think there's more granularity to measure that back-end time, maybe you're interested in the performance of the task UI itself, for that you can use forum.appian.com/.../Performance_View.html

Thank you !!