helper method use

application_controller.rb

class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  helper_method :current_user
  before_action :require_login

  private 

  def require_login
    unless current_user
      flash[:error] = "You must be logged in to access this section"
      redirect_to root_path # halts request cycle
    end
  end

  def current_user
  	@current_user ||= User.find(session[:user_id]) if session[:user_id]
  end
end

fillable_pdf_form.rb

class FillablePdfForm
  
  require 'dropbox_sdk'
  attr_writer :template_path
  attr_reader :attributes

  def initialize
    fill_out
  end

  def export(output_file_path=nil, tenantname)
    output_path = output_file_path || "tmp/#{tenantname}_lease_#{Time.now}.pdf" # make sure tmp/pdfs exists
    pdftk.fill_form template_path, output_path, attributes
    output_path
  end

  def get_field_names 
    pdftk.get_field_names template_path
  end

  def template_path 
    @template_path ||= user.mlease.url # this is where the error occurs, so I need a helper method to pull the current_user and then get the mlease url. Please help ! :)
  end

  protected

  def attributes
    @attributes ||= {}
  end

  def fill(key, value)
    attributes[key.to_s] = value
  end

  def pdftk
   
    @pdftk ||= PdfForms.new(ENV['PDFTK_PATH'] || '') # On my Mac, the location of pdftk was different than on my linux server.
  end

  def fill_out
    raise 'Must be overridden by child class'
  end

end

When you initialize your FillablePdfForm via FillablePdfForm.new(), supply as an argument the current user, e.g.:

  FillablePdfForm.new(current_user: current_user)
  #or
  FillablePdfForm.new(current_user)