I129 is the H1b petition, it has all the information regarding your work, your client/company's information, your own information, what is the job role and how you fit into that job role. Reciept number just indicates that USCIS is processing your case and is helpful in tracking the case.
Once I129 is approved you need to get your passport stamped with H1B visa. You would need to get an appointment with the US consulate in India for the interview.
I797 is the approval notice which specifies the validity period of the H1 and also serves as a proof that you have an H1. Congratulations for the approval and best of luck for the next steps.