Harness does not send donors one comprehensive EOY (end-of-year) receipt for tax purposes because...
We send one-time and monthly donors email receipts to the donor immediately after their donation for their acknowledgment/records
We provide admins the ability to view/download a donor's receipt (#8) in the event the donor lost the email receipt or is unable/unwilling to access their personal Donor Dashboard
We have no way of knowing a donor's comprehensive giving history throughout the year that could include offline gifts like cash/check/in-kind/endowment/stock, etc., or gifts made through other software (ex: online auction/events, etc.)
What most partners do and we recommend is to download your comprehensive Donation Report (choose your timeframe before downloading) & import that CSV/Excel file into your CRM (donor management system). Your CRM is/should be the primary place where you're keeping track of a donor's entire giving history for the year & most CRM's offer a template you can use (free online templates).