If you had a spouse during the current income year, you must complete Spouse details. If you do not know the spouse's taxable income then you should make a reasonable estimate.
To complete spouse details using F10 Fetch spouse details functionality
If your spouse's details are in the data base then click label K to open the Select Return index and automate the completion of all the spouse's details and income.
You should use the F10 feature to avoid incorrect data entry for the spouse and consequent F3 validation errors.
The spouse's return should be completed first. This avoids having to F10 again to refresh the spouse's details or amounts. In any event it is the safest and easiest way to complete Spouse details as it saves keying errors and time.