Il faut utiliser addField : https://help.adobe.com/en_US/acrobat/acrobat_dc_sdk/2015/HTMLHelp/Acro12_MasterBook/JS_API_AcroJS/Collection_methods.htm?rhhlterm=addField&rhsyns=%20#XREF_23829_addField
Exemple :
var name = « monBouton »;
var type = « button »;
var page = 0;
var location = [100, 472, 172, 400];
var myField = this.addField(name, type, page, location);