Custom Input is an add-on for the Payment Button for PayPal WordPress plugin (also known as WP PayPal or WordPress PayPal) that can be used to show a text box at PayPal checkout. The text box can used to collect custom data from buyers.
How Custom Input with WP PayPal Works
When a WP PayPal payment button is rendered on the front end with custom input enabled, a text box will appear that will let buyers enter any data. This can be useful if a buyer would like to include a custom note or special instructions.
The default label for the custom input field (Enter any special instructions) can be customized in the add-on settings (WP PayPal > Custom Input).
How to Enable Custom Input
In order to enable custom input for a WP PayPal button, you need to set the custom parameter empty in the shortcode.
[wp_paypal button="buynow" name="My product" amount="1.00" custom=""]