it is very important to be able to send a pledge bill (in the mail as well) without a specific amount we have people who pledge to give and dont say how much they want to give you and you just want to remind them about their pledge so we want to mail them something so that they mail back a check or make a payment

donate 24 doesn't give the option to choose a campaign

with donate24 you need to set the amount and payment info, I don't see an option to create a link for a donation with no amount

You can send him the donate24 link, find it on the DRM below on the left side

Make a option to be able to send a link to a donor to sponsor any amount they like, without having to set the donation amount.