I have made and donated over 3

[Critter-3]

Just enter the donations in the charity section of the deductions & credits tab as normal… note that the $300 has to be cash..... donating goods or services aren't eligible for the $300 deduction. 

To enter charitable donations -

• Click on Federal Taxes (Personal using Home and Business)
• Click on Deductions and Credits
• Click on I'll choose what I work on (if shown)
• Scroll down to Charitable Donations
• On Donations to Charity in 2020, click on the start or update button

Or enter charitable donation in the Search box located in the upper right of the online program screen. Click on Jump to charitable donation

The program will enter the cash contribution on your federal tax return, Form 1040 Line 10b as an Adjustment to income if your total itemized deductions are not greater than your Standard Deduction.