By default, the donation receipt your supporters will receive will list Donations as 100% Tax-Deductible and will include the tax-deductible disclaimer for 501(c)3 corporations. If this does not apply to your organization, you can change these settings in the Donation Tool Settings for your campaign:
To edit the tax deductible settings for your campaign, go to Campaigns > Edit This Campaign > Manage Settings.
Click the Edit button next to the Donations/Payments frequency (One-Time, Monthly Recurring, Quarterly Recurring and/or Annual Recurring) featured in your campaign.
Set a Tax-Deductible Percentage for Campaign Contributions
Don't forget to click Save, and your changes will be reflected in your campaign for all future transactions!