HMRC Home Office Allowance


I'm using Sage Business Cloud Accounting for my Business / Sole Trader / Self assessment. I used to use Quick books and that automatically calculated my HMRC allowance for using my home as an Office (£18 PM Fixed Allowance deductible Expense). Is there any way in Sage of Entering this allowance so as to correctly calculate my complete Tax Return for Year ending April 2020 or will Sage simply only do my business expenses therefore having to enter only on my Online return.