Will I have to provide proof of my donation to Irs?

[mesquitebean]

First of all, the donation must be to an IRS-defined qualified organization.

Please describe the donation.  What kind of donation--cash, items, stock, etc.?
It may have certain record-keeping requirements.  What is the approximate value?
Some large donations require an appraisal.

You'll likely get some comments in this forum today.   In the meantime, here's some information about charitable contributions in IRS Pub. 526:
<a rel="nofollow" target="_blank" href="https://www.irs.gov/publications/p526">https://www.irs.gov/publications/p526</a>

[tdenice90]

I had a friend drop off close to $500 in baby clothes and furniture to goodwill but never received reciepts

[Hal_Al]

Goodwill asks you if you want a receipt when you drop the stuff off. They hand it to you at that time. They do not mail you a receipt, later.
You do not send any receipts to the IRS when you file your tax return. You only need a receipt if you are audited. That's unlikely.

[AnnetteB · Accepted solution]

In addition to the good information shared by SuperUsers epo39b and Hal_Al, take a look at the following TurboTax article which answers the question “Do I need a receipt for my donation?” and describes the documentation that you should have for different types and amounts of donations to charitable organizations: 

https://ttlc.intuit.com/replies/4201682