In several countries, rent paid by an employee or a self-employed person can reduce taxable income under specific allowances — but the tax authority typically wants documentation, not just a claim, before honoring it.
Why receipts matter more than a lease alone
A lease agreement shows what you agreed to pay; it doesn't prove you actually paid it each month. Receipts (or clear bank transfer records tied to rent) are usually what a tax authority actually wants to see for the deduction to hold up.
What tends to be requested
Commonly: the landlord's name and ID/tax details, the property address, monthly amount, and receipts or a signed statement covering the claimed period. Requirements vary meaningfully by country, so this is general context, not a specific checklist to follow blindly.
Keep a full year's worth together, not scattered
Whatever the specific rule where you live, having twelve consistent, dated receipts ready at filing time is far less stressful than reconstructing months of payment history from memory or scattered bank statements.
If your landlord is reluctant to provide receipts
Some landlords avoid issuing formal receipts to keep rental income less visible. If a deduction genuinely depends on documentation, it's worth raising this directly and early, rather than discovering the problem at tax time.