Contact Management with time\date stamp

Contact Management with time\date stamp

I created a form to enter customer information.  I have two follow up questions based on that.

1.) Our clients call and give us special instructions for future jobs.  What I want to do, is to enter notes when a client calls and have that be date/time stamped.  A client eventually will have multiple notes with different date/time stamps.

2.)  I am also going to create another form called inventory.  All our clients can have inventory with us.  I want to include a drop down that has all the clients already entered through the first form I created to enter clients.  So only contacts entered in the first form can have inventory.

Any help will be appreciated.

Thanks.