You can do it like that:

Dear friends and supporters,

"I am launching a fundraising campaign for [Name of the recipient or the purpose of the donation]. If you're interested in contributing your support through the Lightning Network, please follow the instructions below.

Donation address: [Provide the Lightning Network address of the recipient]"

Of course, it would be good if the donors transfer the money directly to the wallet of the recipient of the donation - if they zap, they simply send him/her the amount of the zaps received.

I know that's not the best solution - but as long as there isn't another one I think it's ok.