That depends:
For an individual cash contribution of under $250: You must have a bank record (such as a canceled check) or a receipt from the church containing the church’s name, and the date and amount of each cash contribution.
For individual contributions (cash or property) of $250 or more: You must receive a written receipt from the church with the church’s name, the date and amount of each contribution, and states whether you received goods or services for your contributions (and if so, a description and good faith estimate of the value of the goods or services received). If you received no goods or services for the contributions, then the receipt must say so or indicate that only “intangible religious benefits” were received. If you’ve made individual contributions of $250 or more, don’t file your federal income tax return until you receive a contribution statement from your church that satisfies these requirements. Otherwise, your contributions may not be deductible. Canceled checks cannot be used to substantiate cash contributions of $250 or more.
For non-cash property valued at $500 or more: Other rules apply (see instructions to IRS Form 8283). If the value is more than $5,000, you must obtain a qualified appraisal of the property and attach an “appraisal summary” (IRS Form 8283) to the tax return on which the contribution is claimed. Some exceptions apply.