I tested this on excel but can not translated to Sharepoint. I am trying to test for example if Column C has date that is greater than the one in column D = Submitted on time, if column C's date is less than the one in Column D than item was submitted late, but in some cases column D will be blank I want it to return Pending.
=IF(D5="","Pending Submission",IFS(C5>D5,"Submitted on time",C5<D5,"Late"))
No, the IF function is supported in SharePoint formulas, but the IFS is not. But you can create a deeply nested IF condition where another IF function is used the third parameter (the "else" condition), so using the formula you presented you can achieve the same with:
=IF([SubmissionDate]="","Pending Submission",IF([DeadlineDate]>[SubmissionDate],"Submitted on time",IF([DeadlineDate]<[SubmissionDate],"Late")))
