MK
Michał Kowalczyk
Tax advisor, KSeF expert
Michał Kowalczyk specializes in bookkeeping digitalization — KSeF, JPK, e-Doręczenia. Writes about technical aspects of implementing new systems and regulatory obligations.
Articles by author (5 articles)
Electronic Invoice Archiving — How Long and How to Store?
Electronic invoice archiving: How many years to keep invoices? 2026 regulations, KSeF, 5-year...
Michał Kowalczyk
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E-Delivery 2025 — New Requirement for Entrepreneurs
E-Delivery 2025 — new requirement for companies. Check who must register, deadlines, how to...
Michał Kowalczyk
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JPK_VAT in 2026 — New Requirements and Filing Deadlines
JPK_VAT in 2026 — complete guide to new requirements and filing deadlines. JPK_V7M structure,...
Michał Kowalczyk
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KSeF — Penalties for Non-implementation from 2026
KSeF — penalties for non-implementation from 2026. Sanctions, implementation schedule, tax...
Michał Kowalczyk
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Best Invoicing Software 2026 — Ranking
Ranking of best invoicing software 2026. Comparison: Fakturownia, inFakt, wFirma, iFirma,...
Michał Kowalczyk
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