The cost of accounting software like QuickBooks (QB) and GoSimpleTax is considered an allowable expense, sjr. Allow me to elaborate.
Allowable expenses refer to costs associated with operating your business, excluding funds withdrawn from the company for personal purchases.
Regarding categorization in QB, dues and subscriptions are classified as business expenses.
For further information about deduction categories you can claim as allowable expenses on your Self Assessment tax return, check out this link: Allowable and disallowable.
Moreover, I'll add this article to help you improve cash flow management: Categorise transactions in QuickBooks Self-Employed.
I'll be here if you need help managing your expenditures in QB Self-Employed. Just add a reply below. Stay safe!