At Board level > Setup > Class info > Codes, you have to ensure the K course are in your Code table. 

Once it is verified, go to your School level > Student records > Achievement > Completed Courses > "+" > select the K course > in Mark,  insert "L" > in Credits attempt, insert "1" > in Credits earned, insert "0" 

Add the information for the Completion date and for which school it was completed 

Then in the section OST notes column check the Modified curriculum > SAVE 

On the Student’s transcript, it will show the Mark "L" will show as ALT and "N/A" will show in the Grade & Credit column as well as the A & M in the Notes column.