2. In the left-hand menu, click Donate to Wikipedia.
3. You’ll set your donation up in the window on the right-hand side here. Click the buttons below “Donation Amount” to select if your donation will be one-time or recurring monthly, your donation amount, and whether you will be paying for your donation through a debit/credit card or the online money management service PayPal.
4. Next, you’ll have to input your billing information. Assuming that you want to pay with a credit or debit card, click the boxes under “Billing Information” and type in or select your first name, last name, street address, city, territory, mailing code, and email address.
After that, click the button beside the type of card you want to use. Then, click in the boxes below your choice and type in or select your card number, the month and year that it expires, and its security code (click What Is A Security Code? if you need help finding it). When you’re done, click Continue.
You will receive a confirmation e-mail when you’re finished. Congratulations on making a contribution to Wikipedia and its mission!