Will it be necessary to provide proof of contributions made to my church?

[HelenC12]

No, you don't have to send in proof of your church contributions but you should have proof in order to claim the contribution deduction. Keep the proof with your tax documents in case you get audited. 

[Opus 17]

You are required to have proof, although you do not attach it to your tax return. Instead, save it with your important papers for at least three years in case of audit.

For money donations, you are required to have a bank record or other documentation of the transaction. This might be a credit card statement, a credit card receipt, an automatic bank draft, or a canceled check. If you donated more than $75 to the church, they are required to issue you a receipt or statement which is also acceptable proof.  If you just put cash into the collection plate and did not attach your name so that the church could give you a receipt, then you will not have adequate proof in case of audit and the deduction will probably be disallowed. However, most taxpayers are never audited.