If you are referring to donating to the non-profit MZLA Technologies Corporation. From the FAQ on https://www.thunderbird.net/donate/ <blockquote>What are the ways I can give? You can donate online securely by credit card or PayPal, Google Pay, Apple Pay, and by bank transfers through SEPA, iDEAL and ACH. Give in your local currency! We accept over 100! Choose yours from the drop down menu next to ‘Amount’. You can give offline in USD only by mailing a check or money order made payable to "MZLA Technologies Corp". Mail to: MZLA PO Box 25718 Pasadena CA 91185-5718 Please include your email address on the memo line of your check to help us track and attribute your gift. We can only send acknowledgement receipts by email. Give the gift of your time! If you would like to learn how to contribute to Thunderbird in other ways such as coding, translating or testing, please visit our Participate page.</blockquote> If you still have questions about donating then use this form https://www.thunderbird.net/donate/help