How to create a reminder email after 3 days?

You could consider 2 options here (and there probably are others as well):

1. pause your workflow for 3 days....
2. add a (hidden) column "3 day remainder" in which you store current date + 3 days and have a daily scheduled site workflow running on all items where "3 day remainder" = today in order to send out the remainder email. By getting the Ids in a collection and using a Foreach loop you can lookup the item details for use in the remainder email.

what should be the reminder mail sent after three days for?

from your workflow snippet it doesn't seems it would wait for any (task) action from an user. 

how can you be sure that notification still should be sent or not?

Hi Jean-Pierre, 

Would the daily scheduled workflow be set using a site workflow?

Also, how do I get the Ids and put them in a collection? Would that be done on the list level or the site workflow level?

Thanks!

Hi Marian,

When the user uploads a document, a reminder should be sent three days later if the status still says pending.

Indeed a scheduled workflow. Which has an List Query action for your list with a Filter for the date comparison and storing the resulting list IDs into a collection workflow variable. Where you can use the foreach to go through each found list item ID, get some more item properties to be used in your reminder email.

However, if the reminder should be send 3 days after the task's due date then you better use the Reminder option of the task action.

Btw: I assume that your switch action is following a task action.

if you request someone to review/approve a document, the best practice is to assign him a task.

at one hand it makes the user to take the action, at the other it pauses workflow until task is responded so you can react on task decision. 

task actions supports notifications/escalation, which are sufficient for simple scenarios.

for complex scenarios you might decide to design an extra workflow.

My switch is based on what a user selects from the options (Approve, Approve with feedback, etc.)

Hi ,

Same task I'll developng can you please suggest me regardimg this task, I'm new in Nintex workflow.

Or can you mail me your mentioned workflow config busniess logic.

Thanks