This post gives you the code for creating members programmatically in Umbraco.

When you use this code, you can pass in the member's username, name, email address and optionally you can pass in their password and optionally assign them to a role/group.

It is currently set up to return the id of the member, but if you wanted to, you could change it to return the random password it created for you.

using Umbraco.Core;

/// <summary>
/// Creates an Umbraco member and assigns them to a role/group if you wish. Returns the member Id.
/// </summary>
/// <param name="username">The username for the member</param>
/// <param name="name">The name of the member</param>
/// <param name="email">The email address for the member</param>
/// <param name="password">A predefined password for the member (leave blank if you want a random password to be created)</param>
/// <param name="roleName">A role / group to assign the member to</param>
/// <returns>Member Id</returns>
public static int CreateMember(string username, string name, string email, string password = null, string roleName = null)
{
  //Create the member
  var member = ApplicationContext.Current.Services.MemberService.CreateMember(username, email, name, "Member");
 
  //Set them to be approved
  member.IsApproved = true;
 
  //Save the member before adding a password or assigning them to a role.
  ApplicationContext.Current.Services.MemberService.Save(member);
 
  //if no password was provided, create a random one here, so people can't login with an empty password.
  if (string.IsNullOrEmpty(password))
  {
    password = Guid.NewGuid().ToString().Substring(0, 8);
  }
  ApplicationContext.Current.Services.MemberService.SavePassword(member, password);

  //If a role name was passed in, assign them to the role here.
  if (!String.IsNullOrEmpty(roleName))
  {
    ApplicationContext.Current.Services.MemberService.AssignRole(member.Id, roleName);
  }
  return member.Id;
}

Hopefully this post will be useful for some of you.

Thanks

Paul