Some publishers will agree to accept an email agreement from the person. The important thing is to receive the permissions and have them on file. A few publishers want them sent with the manuscript and kept by them.
Here is the form letter I sent to 17 people who had stories we wanted to use. All of them agreed to let us. Only two of them asked for minor changes. (The publisher insisted on the legalese.)
I am the author of 90 Minutes in Heaven. My publisher, Baker Publishing Group, wants to put out a special edition with selections from the book and include a section called "Letters from the Gulf." (See below.)
This is to request you to grant permission to me, to Baker Publishing Group, and their licensees, successors and assigns, to include the material indicated below in all editions and derivations of the work in all languages throughout the world and in the advertising and promotion thereof in all media now known or hereafter devised.
Credit will be given in the form you specify below, either on the same page with the photos, on the copyright page, or in a separate section for credits.
In signing below, you represent that you are the sole owner of the rights granted herein, and that the material indicated below does not infringe on the copyright, privacy right, or other rights of anyone.
Please sign a copy of this and send it to my co-author, Cecil Murphey at . . .
Whenever I use a person's name in my book
I get signed permission from that person.